Case: 19-1169   Document: 52    Page: 1     Filed: 02/04/2020




   United States Court of Appeals
       for the Federal Circuit
                 ______________________

     SAMSUNG ELECTRONICS AMERICA, INC.,
                 Appellant

                           v.

           PRISUA ENGINEERING CORP.,
                   Cross-Appellant
               ______________________

                  2019-1169, 2019-1260
                 ______________________

     Appeals from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in No. IPR2017-
 01188.
                  ______________________

                Decided: February 4, 2020
                 ______________________

     RICHARD L. RAINEY, Covington & Burling LLP, Wash-
 ington, DC, argued for appellant. Also represented by
 KRISTIN COBB, ROBERT JASON FOWLER.

    JOHN C. CAREY, Carey, Rodriguez, Greenberg & Paul,
 LLP, Miami, FL, argued for cross-appellant.
                 ______________________

 Before PROST, Chief Judge, NEWMAN and BRYSON, Circuit
                        Judges.
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 BRYSON, Circuit Judge.
      Samsung Electronics America, Inc., appeals from a de-
 cision of the Patent Trial and Appeal Board in an inter
 partes review proceeding. Samsung petitioned the Board
 to rule that certain claims of U.S. Patent No. 8,650,591
 (“the ’591 patent”), owned by cross-appellant Prisua Engi-
 neering Corp. (“Prisua”), were unpatentable. At the con-
 clusion of the proceeding, the Board held that claim 11 of
 the ’591 patent was unpatentable based on obviousness.
 However, the Board declined to analyze whether claims 1–
 4 and 8 were unpatentable as anticipated or obvious, be-
 cause it concluded that those claims were indefinite.
     On appeal, Samsung contends that the Board should
 have canceled claims 1–4 and 8 for indefiniteness. In the
 alternative, Samsung argues that even if the Board was
 not statutorily authorized to cancel those claims for indefi-
 niteness, it should have assessed whether they would have
 been anticipated or obvious in view of the cited prior art.
 Prisua cross-appeals from the Board’s ruling that claim 11
 was unpatentable for obviousness. We affirm in part, re-
 verse in part, and remand.
                               I
                              A
      Congress has long permitted parties accused of patent
 infringement in federal court to challenge the validity of
 the asserted patent claims on any ground specified in part
 II of the Patent Act as a condition for patentability and for
 failure to comply with any requirement of 35 U.S.C. § 112.
 See 35 U.S.C. § 282(b)(2)–(3). Over the last few decades,
 Congress has supplemented federal court litigation by cre-
 ating several administrative processes that authorize the
 Patent and Trademark Office (“PTO”) to reconsider and
 cancel wrongly issued claims in some circumstances.
     In 1980, Congress established a regime known as “ex
 parte reexamination.” See Act to Amend the Patent and
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 Trademark Laws, Pub. L. No. 96-517, 94 Stat. 3015 (1980),
 codified at 35 U.S.C. § 301 et seq. Ex parte reexamination
 gives “[a]ny person at any time” the right to “file a request
 for reexamination” based on certain prior art “bearing on
 the patentability” of an already-issued patent. 35 U.S.C.
 §§ 301(a)(1), 302. After institution, an ex parte reexamina-
 tion follows essentially the same back and forth process be-
 tween the patent owner and the examiner as in the initial
 PTO examination. 35 U.S.C. § 305.
     Congress subsequently created a procedure known as
 “inter partes reexamination.” See Optional Inter Partes
 Reexamination Procedure Act of 1999, Pub. L. No. 106-113,
 113 Stat. 1501A-567, codified at 35 U.S.C. § 311 et seq.
 (2006 ed.) (superseded). Inter partes reexamination gave
 third parties greater opportunities to participate in the
 reexamination process, but otherwise proceeded much like
 an ex parte reexamination.
     The Leahy-Smith America Invents Act (“AIA”), Pub. L.
 No. 112-29, 125 Stat. 284 (2011), replaced inter partes
 reexamination with “inter partes review,” the procedure at
 issue in this case. See 35 U.S.C. §§ 311–19. Inter partes
 review, commonly referred to as IPR, provides patent chal-
 lengers with even broader rights to participate in the pro-
 cess of re-evaluating patents, but it also sets limits on the
 process. A petition for inter partes review, for example, can
 request cancellation of claims “only on a ground that could
 be raised under section 102 or 103 [of the Patent Act] and
 only on the basis of prior art consisting of patents or
 printed publications.” 35 U.S.C. § 311(b).
     The AIA also created another administrative process
 called “post-grant review.” See 35 U.S.C. §§ 321–29. Un-
 like a petition for inter partes review, a petition for post-
 grant review can request cancellation of patent claims “on
 any ground that could be raised under paragraph (2) or (3)
 of section 282(b) [of the Patent Act] (relating to invalidity
 of the patent or any claim),” the same invalidity defenses
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 long available to defendants accused of patent infringe-
 ment in federal district court. 35 U.S.C. § 321(b).
     Although a petition for inter partes review is limited to
 a narrow set of grounds, it can be requested at any time
 during a patent’s enforceability period, with certain re-
 strictions. 35 U.S.C. §§ 311(c), 315(b). By contrast, the
 broad range of grounds that may be raised in a post-grant
 review petition are available only for a limited time after
 the patent is issued. 35 U.S.C. § 321(c).
                               B
       In 2010, Dr. Yolanda Prieto applied for a patent aimed
 at providing a “new and unique form of enhancing” a user’s
 multimedia entertainment experience. ’591 patent, Ab-
 stract. The PTO granted the application in 2014. The is-
 sued patent, entitled “Video Enabled Digital Devices for
 Embedding User Data in Interactive Applications,” is di-
 rected to “generating an edited video data stream from an
 original video stream” by “substituting at least one object
 . . . in said original video stream by at least a different ob-
 ject.” ’591 patent, col. 1, ll. 43–47. Figure 3 illustrates the
 operation of the video image substitution according to one
 embodiment:
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 As illustrated, a user can insert a selected image, such as
 a face of the user’s choosing, in place of the face of the figure
 in the original video. Id. at col. 3, line 66, through col. 4,
 line 2.
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      Claims 1–4, 8, and 11 of the ’591 patent are at issue in
 this appeal. The claims are directed to methods and appa-
 ratuses for “generating a displayable edited video data
 stream from an original video data stream.” ’591 patent,
 col. 7, ll. 14–16; id. at col. 8, ll. 28–29. Independent claim
 1 reads in full as follows:
          1. An interactive media apparatus for generat-
     ing a displayable edited video data stream from an
     original video data stream, wherein at least one
     pixel in a frame of said original video data stream
     is digitally extracted to form a first image, said first
     image then replaced by a second image resulting
     from a digital extraction of at least one pixel in a
     frame of a user input video data stream, said appa-
     ratus comprising:
     an image capture device capturing the user input
     video data stream;
     an image display device displaying the original
     video stream;
     a data entry device, operably coupled with the im-
     age capture device and the image display device,
     operated by a user to select the at least one pixel in
     the frame of the user input video data stream to use
     as the second image, and further operated by the
     user to select the at least one pixel to use as the
     first image;
     wherein said data entry device is selected from a
     group of devices consisting of: a keyboard, a dis-
     play, a wireless communication capability device,
     and an external memory device;
     a digital processing unit operably coupled with the
     data entry device, said digital processing unit per-
     forming:
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    identifying the selected at least one pixel in the
    frame of the user input video data stream;
    extracting the identified at least one pixel as the
    second image;
    storing the second image in a memory device oper-
    ably coupled with the interactive media apparatus;
    receiving a selection of the first image from the
    original video data stream;
    extracting the first image;
    spatially matching an area of the second image to
    an area of the first image in the original video data
    stream, wherein spatially matching the areas re-
    sults in equal spatial lengths and widths between
    said two spatially matched areas; and
    performing a substitution of the spatially matched
    first image with the spatially matched second im-
    age to generate the displayable edited video data
    stream from the original video data stream.
 ’591 patent, cl. 1. Claims 2–4 and 8 depend from claim 1
 and add several limitations that are not pertinent to the
 resolution of this appeal. Independent claim 11 is a method
 claim that tracks the limitations of apparatus claim 1, with
 some minor differences. In particular, claim 11 does not
 have a limitation corresponding to claim 1’s requirement of
 “an image display device displaying the original video
 stream.” Id. On the other hand, claim 11 adds limitations
 that require the computation of “motion vectors associated
 with the first image” and the application of those motion
 vectors “to the second image, wherein the generated dis-
 playable edited video data stream resulting from the sub-
 stitution maintains an overall motion of the original video
 data stream.” Id.
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                               C
     After the ’591 patent issued, Dr. Prieto formed Prisua
 to commercialize the invention claimed in the patent. In
 2016, Prisua sued Samsung Electronics America, Inc., and
 several other Samsung entities for patent infringement.
 Prisua alleged that the “Best Face” feature on several Sam-
 sung devices, including cell phones, infringed claims 1, 3,
 4, and 8 of the ’591 patent. The “Best Face” feature, ac-
 cording to Prisua, allowed the accused devices to capture a
 burst of images and then replace unwanted facial images,
 such as images captured when someone was blinking, with
 better images from other frames in the same burst. 1
     After being sued, Samsung petitioned for inter partes
 review of claims 1–4, 8, and 11 of the ’591 patent on four
 separate grounds. The Board initially determined that it
 would review only whether a U.S. patent application pub-
 lication known as Sitrick rendered claim 11 obvious. The
 Board declined to institute review of claims 1–4 and 8 on
 any ground, because it concluded that it could not deter-
 mine the scope of those claims.
     The Board concluded that there were two impediments
 to determining the scope of claim 1. First, the Board found
 that it was “unclear whether claim 1 covers, for example,
 an apparatus that includes a data entry device capable of
 being operated by a user to select the at least one pixel, or
 covers only the user actually operating the data entry de-
 vice to select the at least one pixel.” Samsung Elecs. Am.,
 Inc. v. Prisua Eng’g Corp., No. IPR2017-01188, 2017 WL



     1    After a trial in the United States District Court for
 the Southern District of Florida, the jury found that Sam-
 sung willfully infringed the asserted claims and awarded
 Prisua $4.3 million in damages. That action has been
 stayed pending this proceeding; the verdict in that case is
 not at issue in this appeal.
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 4570373, at *5 (P.T.A.B. Oct. 11, 2017) (“Institution Deci-
 sion”) (emphasis in original). For that reason, the Board
 concluded that claim 1 was indefinite under this court’s de-
 cision in IPXL Holdings, LLC v. Amazon.com, Inc., 430
 F.3d 1377, 1384 (Fed. Cir. 2005). Institution Decision, 2017
 WL 4570373, at *5-6. The Board also concluded that the
 “digital processing unit” limitation in claim 1 “invoke[d]
 § 112, sixth paragraph” and that the petition failed to iden-
 tify any corresponding structure, as required by section 112
 and the pertinent PTO regulation, 37 C.F.R. § 42.104(b)(3).
 Institution Decision, 2017 WL 4570373 at *6 (citing Wil-
 liamson v. Citrix Online, LLC, 792 F.3d 1339, 1348 (Fed.
 Cir. 2015) (en banc)). The Board found that claims 2–4 and
 8, which depend from claim 1, were indefinite for the same
 reasons. Because the Board determined that it was unable
 to construe claim 1 or dependent claims 2–4 and 8, it con-
 cluded that the petitioner had not “established a reasona-
 ble likelihood of prevailing in showing that claims 1–4, and
 8 are unpatentable under any of the asserted grounds.” Id.
     As the IPR briefing was drawing to a close, the Su-
 preme Court decided SAS Institute, Inc. v. Iancu, 138 S. Ct.
 1348 (2018), in which the Court held that when the Board
 institutes an IPR, it may not pick and choose which claims
 it will address, but must address the patentability of every
 claim challenged by the petitioner. Accordingly, the Board
 modified its institution decision to include all the chal-
 lenged claims and all the grounds presented in the petition.
 The Board also allowed the parties to file supplemental
 briefs and evidence, but only to address the newly added
 claims and grounds.
      In its supplemental briefing, Prisua stated that it did
 not agree with the Board’s indefiniteness determinations.
 Despite that, Prisua argued that because Samsung had
 failed to prove the claims were definite, the Board should
 not apply the prior art to the claims. Prisua also contended
 that the Board did not have the statutory authority to can-
 cel claims for indefiniteness during an IPR.
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      In response, Samsung urged the Board to cancel claims
 1–4 and 8 based on the Board’s determination that those
 claims were indefinite under this court’s analysis in IPXL.
 In the alternative, Samsung argued that even if the Board
 could not cancel the claims for indefiniteness, it could still
 apply the prior art to the claims despite the IPXL issue. In
 support of that contention, Samsung argued that because
 the uncertainty regarding claim scope resulted from the
 combination of two statutory classes of invention, a manu-
 facturer or seller of the claimed device would not know
 when infringement occurred. But that, according to Sam-
 sung, would not pose an obstacle to determining whether
 those claims could be measured against the prior art. Sam-
 sung also argued that the term “digital processing unit”
 constituted a sufficient recitation of structure and did not
 invoke means-plus-function analysis under 35 U.S.C. § 112
 ¶ 6.
     In its final written decision, the Board repeated its con-
 clusion that claims 1–4 and 8 were indefinite under IPXL.
 Samsung Elecs. Am., Inc. v. Prisua Eng’g Corp., No.
 IPR2017-01188, 2018 WL 5274000, at *7–8 (P.T.A.B. Oct.
 2, 2018) (“Final Written Decision”). In addition, the Board
 again held that claim 1 and its dependent claims invoked
 section 112, paragraph 6, for the “digital processing unit”
 element, and that because there was no corresponding
 structure in the specification, the Board could not apply the
 prior art to the claims. Id. at *9. The Board therefore held
 that Samsung had not established that claims 1–4 and 8
 were unpatentable under any of the asserted grounds. Id.
     With respect to claim 11, the Board analyzed whether
 that claim would have been obvious in view of Sitrick, the
 sole originally instituted ground of review. After reviewing
 various record materials, including competing expert testi-
 mony, the Board found that all of the limitations of claim
 11 would have been obvious in light of Sitrick, including
 the “digital processing unit” limitation. Id. at *11-19. The
 Board therefore held claim 11 to be unpatentable.
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                              II
     On appeal, Samsung challenges the Board’s decision
 not to cancel the claims it found indefinite. In the alterna-
 tive, Samsung contends that the Board should have ap-
 plied the cited prior art to those claims.
                              A
      We reject Samsung’s contention that the IPR statute
 authorizes the Board to cancel challenged claims for indef-
 initeness. In Cuozzo Speed Techs., LLC v. Lee, the Su-
 preme Court said the Patent Office would be acting
 “outside its statutory limits” by “canceling a patent claim
 for ‘indefiniteness under § 112’ in inter partes review.” 136
 S. Ct. 2131, 2141–42 (2016). This court subsequently ech-
 oed that view, stating—albeit in a non-precedential opin-
 ion—that “[i]n an IPR, the Board cannot declare claims
 indefinite.” Google LLC v. Network-1 Techs., Inc., 726 F.
 App’x 779, 782 n.3 (Fed. Cir. 2018) (citing 35 U.S.C.
 § 311(b)); see also Neptune Generics, LLC v. Eli Lilly & Co.,
 921 F.3d 1372, 1378 (Fed Cir. 2019) (holding that the Board
 is not authorized to address challenges to patent eligibility
 under 35 U.S.C. §101 in an IPR proceeding: “Congress ex-
 pressly limited the scope of inter parties review to a subset
 of grounds that can be raised under 35 U.S.C. §§ 102 &
 103.”).
     Samsung asks us to reject those statements as dicta
 and to hold that even though the Board may not institute
 inter partes review based on a claim’s indefiniteness, it
 may cancel such a claim on indefiniteness grounds once it
 has instituted review on statutorily authorized grounds.
 We are not persuaded by Samsung’s arguments; we hold
 that the Board may not cancel claims for indefiniteness in
 an IPR proceeding.
     The statutory provisions governing the inter partes re-
 view process do not permit the Board to institute inter
 partes review of claims for indefiniteness. Section 311(b),
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 entitled “Scope,” states that “[a] petitioner in an inter
 partes review may request to cancel as unpatentable 1 or
 more claims of a patent only on a ground that could be
 raised under section 102 or 103 and only on the basis of
 prior art consisting of patents or printed publications.” 35
 U.S.C. § 311(b). Samsung, the petitioner in the IPR pro-
 ceeding below, was thus not permitted to request that the
 Board cancel claims 1–4 and 8 on the ground that they were
 indefinite.
      Nor could the Board cancel those claims as indefinite
 on its own accord. As the Supreme Court explained in SAS,
 Congress “chose to structure a process in which it’s the pe-
 titioner, not the Director, who gets to define the contours”
 of an IPR proceeding. 138 S. Ct. at 1355. “[T]he statute
 envisions that a petitioner will seek an inter partes review
 of a particular kind—one guided by a petition describing
 ‘each claim challenged’ and ‘the grounds on which the chal-
 lenge to each claim is based.’” Id. (quoting 35 U.S.C.
 § 312(a)(3)). After analyzing the IPR statute and its prede-
 cessors, the Supreme Court concluded that it was clear that
 “the petitioner’s contentions, not the Director’s discretion,
 define the scope of the litigation all the way from institu-
 tion through to conclusion.” Id. at 1357. The petition, that
 is, defines the scope of an IPR proceeding, and nothing in
 the IPR statute permits the Board to expand that scope in
 its final written decision.
                              1
     Notwithstanding the foregoing authority, Samsung
 points to several provisions in the IPR statute in an effort
 to show that Congress authorized the Board to cancel
 claims for indefiniteness after an IPR has been instituted.
 None of those provisions, however, supports Samsung’s ar-
 gument.
     First, while section 311(b) limits the scope of an IPR
 petition to certain grounds that could be raised under sec-
 tions 102 and 103, Samsung argues that section 318(a),
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 which relates to the Board’s final written decision, is not so
 limited. Section 318(a) directs the Board to “issue a final
 written decision with respect to the patentability of any pa-
 tent claim challenged by the petitioner and any new claim
 added under section 316(d).” 35 U.S.C. § 318(a). Samsung
 contends that the word “patentability” in section 318(a) is
 broader than the phrase “a ground that could be raised un-
 der section 102 or 103” in section 311(b). The difference,
 according to Samsung, indicates that the permissible scope
 of the Board’s final written decision is broader than the
 permissible scope of the petition and the institution deci-
 sion.
     The problem with that argument is that it divorces the
 final written decision provision, section 318(a), from the
 rest of the inter partes review statute. Section 311(b) says
 that a petitioner may ask the Board “to cancel [challenged
 claims] as unpatentable” on certain 102 and 103 grounds.
 In context, it is clear that section 318(a)’s directive to the
 Board to issue a final written decision on the “patentabil-
 ity” of a challenged claim refers back to the grounds on
 which, under section 311(b), the petitioner may request the
 Board to “cancel as unpatentable” claims of the challenged
 patent, i.e., the designated section 102 and 103 grounds. 2
     Second, Samsung notes that the word “patentability”
 in section 318(a) modifies both “challenged” claims and
 “new” claims that are proposed during the inter partes pro-
 ceeding. For that reason, Samsung suggests, the scope of
 the Board’s review must be the same for both. And because


     2   The Director’s certificate under section 318(b) “con-
 firming any claim of the patent determined to be patenta-
 ble” does not indicate that the Board has analyzed and
 confirmed the patentability of the subject claims against
 any possible ground of invalidity, as Samsung suggests.
 The certificate is merely a reflection of the analysis that
 the Board performed in response to the petition.
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 it is undisputed that the Board may review newly added
 claims for compliance with section 112, Samsung argues
 that the Board must likewise be authorized to review chal-
 lenged claims for unpatentability on section 112 grounds,
 including indefiniteness.
     That argument overlooks the distinction the inter
 partes review statute draws between challenged claims
 and new claims that are added in the IPR proceeding. Sec-
 tion 316(d) allows patent owners to move to amend a patent
 during an IPR proceeding by substituting new or amended
 claims. Unlike section 311(b), section 316(d) does not limit
 the grounds for considering the unpatentability of those
 new claims under provisions other than sections 102 and
 103.
     Because the Board is charged with the responsibility
 under section 318(b) of “incorporating in the patent by op-
 eration of the certificate any new or amended claim deter-
 mined to be patentable,” the Board’s authority with respect
 to new and amended claims necessarily extends to other
 possible grounds of unpatentability, in particular, a failure
 to comply with section 112. Because the statutory provi-
 sions governing challenged claims in an IPR differ im-
 portantly from those governing substitute claims, the term
 “unpatentability” necessarily has a different scope as to
 each.
     Samsung next points to the post-grant review statute
 to support its argument that claims can be cancelled as in-
 definite at the conclusion of an IPR proceeding. Unlike a
 petition for inter partes review, a petition for post-grant re-
 view may be based on “any ground that could be raised un-
 der paragraph (2) or (3) of section 282(b) (relating to
 invalidity of the patent or any claim).” 35 U.S.C. § 321.
 Despite the difference in scope regarding what may be re-
 quested in post-grant review as opposed to inter partes re-
 view, the final written decision provision of the post-grant
 review statute mirrors the final written decision provision
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 of the inter partes review statute. See 35 U.S.C. § 328
 (“[T]he Patent Trial and Appeal Board shall issue a final
 written decision with respect to the patentability of any pa-
 tent claim challenged by the petitioner and any new claim
 added under section 326(d).”) (emphasis added). Because
 there can be no dispute that review of “patentability” in the
 post-grant review statute encompasses indefiniteness,
 Samsung contends that when Congress used the same
 word in the inter partes review statute, it must have meant
 to authorize the Board to consider grounds of unpatenta-
 bility other than those raised in the petition, such as indef-
 initeness.
      To the contrary, the term “patentability” takes its
 meaning in each of the two statutory provisions from its
 particular context. Congress laid out the scope of inter
 partes review in section 311(b), at the beginning of Chapter
 31 of Title 35. It laid out the scope of post-grant review in
 section 321(b), at the beginning of Chapter 32. Congress’s
 use of the word “patentability” in the final written decision
 provision of each chapter—in sections 318(a) and 328(a),
 respectively—most naturally refers to the previously de-
 fined scope of the particular review in question. Patenta-
 bility for purposes of section 318(a) thus refers to the
 limited grounds of unpatentability described in section
 311(b), and patentability for purposes of section 328(a) re-
 fers to the broader grounds of unpatentability described in
 section 321(b).
                               2
     We also do not agree with Samsung’s contention that
 the Board’s inherent authority to perform claim construc-
 tion during an inter partes review means that the Board
 can cancel the claims as indefinite. Although “indefinite-
 ness analysis involves general claim construction princi-
 ples,” Sonix Tech. Co. v. Publications Int’l, Ltd., 844 F.3d
 1370, 1378 (Fed. Cir. 2017), it does not follow that the
 Board may exceed its statutorily limited authority simply
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 because an indefiniteness issue arises during claim con-
 struction. Instead, as discussed above, Congress viewed a
 challenge based on indefiniteness to be distinct from a chal-
 lenge based on sections 102 and 103. As such, the proper
 course for the Board to follow, if it cannot ascertain the
 scope of a claim with reasonable certainty for purposes of
 assessing patentability, is to decline to institute the IPR or,
 if the indefiniteness issue affects only certain claims, to
 conclude that it could not reach a decision on the merits
 with respect to whether petitioner had established the un-
 patentability of those claims under sections 102 or103. 3 It
 would not be proper for the Board to cancel claims on a
 ground that is unavailable in an IPR.
                               3
     In essence, Samsung’s argument is that there is no
 limit to the Board’s authority to make unpatentability de-
 terminations at the conclusion of an IPR proceeding. That
 position is at odds with both the statutory language and
 the case law, and we reject it.
                               B
     Having rejected Samsung’s argument that the Board
 may cancel challenged claims for indefiniteness during an
 IPR, we next address Samsung’s secondary argument that
 the Board should have assessed the patentability of claims
 1 and 4–8 under sections 102 or 103.
     As noted, even though neither party raised the issue of
 indefiniteness below, the Board raised two indefiniteness



      3  To be clear, in cases in which the Board cannot
 reach a final decision as to the patentability of certain
 claims because it cannot ascertain the scope of those claims
 with reasonable certainty, the petitioner would not be es-
 topped by 35 U.S.C. § 315(e) from challenging those claims
 under sections 102 or 103 in other proceedings.
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 concerns sua sponte. First, the Board concluded that claim
 1 was indefinite under IPXL, because the claim recited
 both an apparatus and a method of using that apparatus.
 Final Written Decision, 2018 WL 5274000 at *6. Second,
 the Board concluded that the “digital processing unit” lim-
 itation of claim 1 invoked “means-plus-function” claiming
 under 35 U.S.C. § 112, ¶ 6, and that because Samsung did
 not identify any corresponding structure in the specifica-
 tion, the Board could not apply the prior art to claim 1 or
 its dependent claims. Id. Samsung contends that the
 Board’s analysis of the “digital processing unit” limitation
 was incorrect and that the IPXL issue did not prevent the
 Board from assessing the patentability of claims 1 and 4–8
 under sections 102 or 103.
                               1
     We agree with Samsung that the term “digital pro-
 cessing unit” is not a “means-plus-function” limitation sub-
 ject to analysis under section 112, paragraph 6. Because
 the reference to the digital processing unit does not contain
 the words “means for,” there is a rebuttable presumption
 that section 112, paragraph 6, does not apply to that limi-
 tation. Williamson, 792 F.3d at 1348. That presumption
 can be overcome, but only “if the challenger demonstrates
 that the claim term fails to ‘recite sufficiently definite
 structure’ or else recites ‘function without reciting suffi-
 cient structure for performing that function.’” Id. at 1349.
     The question whether the term “digital processing
 unit” invokes section 112, paragraph 6, depends on
 whether persons skilled in the art would understand the
 claim language to refer to structure, assessed in light of the
 presumption that flows from the drafter’s choice not to em-
 ploy the word “means.” The Board pointed to no evidence
 that a person skilled in the relevant art would regard the
 term “digital processing unit” as purely functional. In fact,
 Prisua argued to the Board, based on testimony from its
 expert (the inventor), that the digital processing unit
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 recited in the claims is “an image processing device that
 people in the art are generally familiar with.” J.A. 896.
      As used in the claims of the ’591 patent, the term “dig-
 ital processing unit” clearly serves as a stand-in for a “gen-
 eral purpose computer” or a “central processing unit,” each
 of which would be understood as a reference to structure in
 this case, not simply any device that can perform a partic-
 ular function. See, e.g., LG Elecs., Inc. v. Bizcom Elecs.,
 Inc., 453 F.3d 1364, 1372 (Fed. Cir. 2006), rev’d on other
 grounds, Quanta Computer, Inc. v. LG Elecs., Inc., 553 U.S.
 617 (2008); Inventio AG v. ThyssenKrupp Elevator Ams.
 Corp., 649 F.3d 1350, 1359 (Fed. Cir. 2011).
     Significantly, that is what the Board found with re-
 spect to the use of the term “digital processing unit” in
 claim 11. Final Written Decision, 2018 WL 5274000, at *14
 (“As a result, we are not persuaded by Patent Owner’s con-
 tention that ‘digital processing unit’ has a narrower defini-
 tion than CPU. Sitrick discloses a general purpose
 computer with a CPU that is capable of performing all of
 the functions recited in claim 11. As a result, we are per-
 suaded that Sitrick’s CPU teaches the recited ‘digital pro-
 cessing unit.’”). Moreover, claim 1 requires that the
 “digital processing unit” be operably connected to a “data
 entry device” such as a keyboard, which in turn is con-
 nected to other components. That portion of claim 1 con-
 stitutes further evidence of the structural nature of the
 term “digital processing unit,” as used in the claim.
     The Board did not treat claim 11’s “digital processing
 unit” as simply a black box recitation of any structure ca-
 pable of providing certain functions. Instead, the Board
 equated the term to a class of known structures—central
 processing units—that could be found in any general-pur-
 pose computer. See Final Written Decision, 2018 WL
 5274000, at *14. The Board’s treatment of the “digital pro-
 cessing unit” limitation in claim 11 as structural in nature
 undermines its conclusion that the same term in claim 1
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 was functional and thus subject to analysis under section
 112, paragraph 6.
     Given the Board’s findings with respect to claim 11, the
 context of the term in the claim at issue, and the presump-
 tion arising from the patentee’s failure to use the “means
 for” formulation, unrebutted by any evidence before the
 Board, we conclude that the Board erred in ruling that the
 term “digital processing unit” does not recite structure and
 instead is a purely functional term. We therefore reject the
 Board’s conclusion that the term “digital processing unit,”
 as used in claim 1, invoked means-plus-function claiming,
 and that for that reason claims 1 and 4–8 cannot be ana-
 lyzed for anticipation or obviousness. 4
                              2
      The Board also concluded that claim 1 was indefinite
 because of an IPXL issue—a finding that neither party dis-
 putes. However, the Board did not address Samsung’s ar-
 gument that the Board could nonetheless apply the prior
 art to claim 1 and its dependent claims for purposes of an-
 ticipation or obviousness analysis. In light of our decision
 to reverse the Board’s decision as to the “digital processing
 unit” term, we believe the Board ended its analysis with
 respect to the IPXL issue prematurely. We therefore re-
 mand for further consideration of that issue.



     4    Pointing to the Board’s reference to 37 C.F.R.
 § 42.104(b)(3), Prisua argues that Samsung’s petition
 failed to present a proper claim construction for claim 1,
 and that the Board’s decision is supportable on that
 ground. The Board, however, referred to the regulation
 only “if one were to contend that claim 1 is an apparatus
 claim whose limitations are merely written in functional
 language.” Final Written Decision, 2018 WL 5274000, at
 *9. Samsung has not made such a contention, and we have
 rejected it.
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      On remand, the Board should address Samsung’s argu-
 ment that the Board may analyze the patentability of a
 claim even if that claim is indefinite under the reasoning
 of IPXL. The rationale of IPXL is that the claim conflates
 elements of both an apparatus and a method, rendering the
 claim indefinite for purposes of determining when infringe-
 ment occurs. But that merely says that the claim is subject
 to invalidation on the ground of indefiniteness. It does not
 speak to whether the claim is also invalid for obviousness,
 regardless of whether it is treated as being directed to an
 apparatus or a method.
      Even though the validity of the challenged claims may
 be subject to question for IPXL-type indefiniteness, that is
 simply another ground on which the claims might be chal-
 lenged in an appropriate forum (other than the Board). See
 Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 453–
 55 (Fed. Cir. 1985) (upholding decision that patent was in-
 valid for both indefiniteness and obviousness); In re Collier,
 397 F.2d 1003, 1004–06 (CCPA 1968) (rejecting claim on
 grounds of indefiniteness and obviousness). It does not
 necessarily preclude the Board from addressing the patent-
 ability of the claims on section 102 and 103 grounds. In the
 remand proceedings, the Board should determine whether
 claim 1 and its dependent claims are unpatentable as an-
 ticipated or obvious based on the instituted grounds. 5



      5  The Board has previously held that IPXL-type in-
 definiteness does not prevent the Board from addressing
 patentability. See Vibrant Media, Inc. v. Gen. Elec. Co., No.
 IPR2013-00172, 2014 WL 3749773 (P.T.A.B. July 28,
 2014), aff’d, 626 F. App’x 1010 (Fed. Cir. 2015). Although
 the Board in this case suggested that its decision in Vibrant
 Media might be inconsistent with this court’s decision in
 Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325, 1332
 (Fed. Cir. 2010), the statement in the Enzo case quoted by
 the Board—that “a claim cannot be both indefinite and
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                              III
     In its cross-appeal, Prisua challenges the Board’s order
 holding claim 11 of the ’591 patent invalid for obviousness
 over the Sitrick prior art reference. We affirm the Board’s
 order with respect to that claim.
                              A
     Prisua contends that Sitrick did not disclose the “cap-
 turing a user input video data stream” limitation, and that
 the Board ignored Prisua’s argument with respect to that
 limitation. Samsung responds that Prisua did not properly
 raise that issue before the Board, and we agree. None of
 the documents Prisua cites establish that Prisua timely
 presented any argument to the Board regarding the “cap-
 turing” limitation.
      The documents Prisua points to as evidence that it pre-
 sented an argument regarding that limitation to the Board
 consist mainly of material submitted during the supple-
 mental briefing. When the Board, in response to the Su-
 preme Court’s decision in SAS, modified its original
 institution decision to include all the claims and grounds
 raised in the petition, the Board authorized the parties to
 file supplemental briefs. The Board ordered that those
 briefs address only the newly added claims and grounds,
 not any issues that were already under review. Because
 the issue of the obviousness of claim 11 in view of Sitrick
 was part of the original institution decision, Prisua’s


 anticipated”—did not involve IPXL-type indefiniteness and
 therefore did not resolve the question presented to the
 Board in this case. Our decision here is limited to IPXL-
 type indefiniteness and does not affect claims that are in-
 definite for other reasons. Moreover, our ruling in this case
 does not affect the disposition of cases in forums that are
 authorized to consider indefiniteness as a basis for invali-
 dating a claim.
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 supplemental briefing did not pertain to that issue. The
 supplemental briefing thus did not bear on the issues in
 Prisua’s cross-appeal, which involves only the obviousness
 of claim 11 in view of Sitrick. 6
                              B
     Prisua next argues that Sitrick does not disclose a
 “data entry device,” as recited in claim 11, and that the
 Board failed to analyze whether the alleged data entry de-
 vice of Sitrick is “operably coupled with the digital video
 capture device,” as claim 11 requires. We conclude that
 substantial evidence supports the Board’s findings that
 Sitrick disclosed the “data entry device,” and that Prisua
 waived any argument regarding the “operably coupled” as-
 pect of the limitation.
     With respect to the “data entry device” limitation, the
 Board found that “a person of ordinary skill in the art
 would have understood Sitrick’s disclosure of a ‘general
 purpose computer’ to include a keyboard,” and that in any
 event it was not necessary for Samsung to establish that
 the general purpose computer disclosed in Sitrick neces-
 sarily has a keyboard. Final Written Decision, 2018 WL
 5274000, at *13.
     Prisua contends that Sitrick does not inherently dis-
 close a keyboard, but Samsung did not argue to the con-
 trary. Instead, Samsung argued only that Sitrick’s general
 purpose computer would necessarily include some type of
 data entry device, a keyboard being one example. After



      6  Prisua made a cursory reference to the “capturing
 a user input video data stream” limitation in the back-
 ground section of its patent owner response, but did not
 discuss that limitation in its nonobviousness argument.
 The Board was therefore correct in stating that Prisua did
 not argue that limitation.
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 considering extensive record materials besides the Sitrick
 reference, including deposition testimony and competing
 expert declarations, the Board agreed with Samsung that
 Sitrick taught a data entry device.
     That conclusion was supported by substantial evi-
 dence. In particular, it was reasonable for the Board to
 conclude that Prisua’s expert, Dr. Prieto, conceded in dep-
 osition that the general-purpose computer disclosed in Sit-
 rick would have a data entry device such as a keyboard.
 Although Dr. Prieto went on to explain that other special
 purpose hardware and software combinations disclosed in
 Sitrick might not always include a data entry device, that
 does not undermine the Board’s conclusion that the dis-
 closed general-purpose computer would include a data en-
 try device. We see no reason to disturb the Board’s
 evaluation and weighing of the evidence on that score.
     We also do not believe the Board improperly skipped
 over the “operably coupled” aspect of the “using a data en-
 try device” limitation, as Prisua suggests. In its prelimi-
 nary patent owner response, prior to the institution of the
 IPR, Prisua argued that a video camera can serve as the
 source of image data, but need not be “operably coupled” to
 a general purpose computer to do so. However, after the
 Board rejected Prisua’s argument in its institution deci-
 sion, Prisua focused on the absence of a “data entry device”
 in Sitrick and did not address the “operably coupled” por-
 tion of that limitation. It was therefore reasonable for the
 Board to conclude that Prisua was no longer pressing any
 argument based on the “operably coupled” language, and
 to focus only on the arguments Prisua was continuing to
 make.
                              C
     Prisua next argues that Sitrick does not teach or sug-
 gest the claimed step of “spatially matching an area of the
 second image to an area of the first image in the original
 video data stream, wherein spatially matching the areas
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 results in equal lengths and widths between said two spa-
 tially matched areas.” That step would, for example, re-
 quire a user replacing an actor’s face with the user’s own to
 make sure the image of the user’s face was modified so that
 it matched the length and width of the image it was replac-
 ing. The Board found that Sitrick taught the use of image
 transformation techniques that met the “spatially match-
 ing” limitation recited in claim 11. The Board’s finding on
 that issue was supported by substantial evidence.
     Prisua contends that although Sitrick discloses several
 image transformation techniques, none of them requires
 that the original and matched areas be of equal lengths and
 widths. Instead, Prisua says that one of the available tech-
 niques is chosen to “obtain the best” results, which is not
 the same as achieving “equal lengths and widths” for the
 original and matched areas. In the Sitrick reference, ac-
 cording to Prisua, achieving “equal lengths and widths” is
 merely a possibility, and thus that limitation is not dis-
 closed sufficiently to establish obviousness.
     In making its findings, the Board weighed both experts’
 testimony regarding the “equal lengths and widths” limita-
 tion, and chose to credit Samsung’s expert’s testimony that
 the “morphing” technique disclosed in Sitrick involves an
 “exact one to one relationship between the first array of co-
 ordinates and the second array of coordinates—to align the
 points of the first image into the points of the second image,
 which would result in equal length and width.” Final Writ-
 ten Decision, 2018 WL 5274000, at *17 (internal quotations
 omitted). That assessment, the Board found, was enough
 to establish that Sitrick discloses the “equal lengths and
 widths” limitation. Prisua does not provide a convincing
 response to that evidence, and we see no reason to disturb
 the Board’s conclusion based on that evidence.
     In an attempt to avoid that natural reading of Sitrick,
 Prisua contends that Sitrick specifically excludes the
 morphing technique, and that the Board therefore should
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 not have relied on the testimony of Samsung’s expert. We
 disagree. Although Sitrick discloses other transformation
 techniques that, unlike morphing, may not necessarily
 have resulted in equal lengths and widths, Sitrick undeni-
 ably discloses using morphing as one option. And the
 Board reasonably concluded that the morphing technique
 results in equal lengths and widths, thus satisfying the
 limitation at issue.
                               D
      Prisua next contends that Sitrick does not teach or sug-
 gest the claimed requirements of selecting, identifying, and
 extracting at least one pixel from the user input video data
 stream to be used as the second image. In the claim, a spa-
 tially matched second image is what ultimately replaces
 the first image in the original video stream.
     Prisua complains that the second image in Sitrick is
 modified before it is inserted in the substitution step,
 whereas the claim, according to Prisua, does not allow the
 second image to be modified before being inserted in the
 substitution step. We do not see how Prisua’s argument
 has any bearing on the claimed requirements of selecting,
 identifying, and extracting at least one pixel from the user
 input video data stream.
     The Board agreed with Samsung’s argument that a
 user operating the Sitrick system would have to select at
 least one pixel in the user input video data stream in order
 for the system to analyze the user selected image. 7 It is
 clear from Sitrick that the selection, identification, and ex-
 traction of at least one pixel in the disclosed system occurs
 before any alleged modification, and those steps are thus
 unaffected by whether there is a subsequent modification.


     7   Contrary to Prisua’s contention, Samsung’s argu-
 ment was not based on inherency, but merely recognized
 that the image to be analyzed consists of one or more pixels.
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 Moreover, even if the inputs in the substitution step are
 modifications of the second image, that is consistent with
 the language of claim 11, which requires that the second
 image be “spatially matched” with the first image. Claim
 11’s “spatially matching” requirement specifically contem-
 plates modifying the second image so that it will have equal
 lengths and widths as the first image it is replacing.
      Prisua also contends that the Board misunderstood the
 pertinent language of claim 11. In its final written deci-
 sion, the Board stated, with respect to Sitrick, that “even
 assuming that user-specified image 137 is a texture map
 by the time it is an input 570 into subsystem 500, that is
 not sufficient to show that an image was not originally se-
 lected, as the claim [of the ’591 patent] requires.” Final
 Written Decision, 2018 WL 5274000, at *13 (emphasis
 added). Prisua argues that the emphasized language indi-
 cates that the Board misunderstood claim 11, because the
 claim recites that “at least one pixel” is selected, not that
 “an image” is selected. The Board, however, had previously
 credited Samsung’s explanation that Sitrick’s “user se-
 lected image” required the selection of at least one pixel.
 The Board’s finding in that regard, which was consistent
 with the testimony of Samsung’s expert, was supported by
 substantial evidence.
                              E
     Lastly, Prisua contends that Sitrick does not teach or
 suggest the limitation of claim 11 that requires applying
 “motion vectors” so that the edited video data stream re-
 sulting from the substitution maintains the overall appear-
 ance of motion produced by the original video data stream.
     That part of claim 11 recognizes that if an original
 video includes motion, one might want the user image that
 is being substituted into the original video to track that
 motion. For example, if the user wanted to replace an ac-
 tress’s face with her own, the user would likely want to
 make sure the actress’s body did not move in a way that
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 left the substituted face behind. In order to accomplish
 that objective, claim 11 requires that the motion vectors of
 the first image be computed and applied to the second im-
 age.
     In concluding that the limitation providing for “apply-
 ing the motion vectors in the second image” was taught in
 Sitrick, the Board reasonably credited Samsung’s expert
 testimony that motion vector information associated with
 the first image in Sitrick would be applied to the second
 image in order to maintain the placement and orientation
 of the second image in relation to the first image.
      The Board found that testimony to be consistent with
 Sitrick’s disclosure that an “association means” would use
 computed motion vector information from a first audiovis-
 ual presentation to associate one or more replacement ob-
 jects (i.e., second images) with a detected reference object
 (i.e., the first image). We therefore conclude that substan-
 tial evidence supports the Board’s finding that the “apply-
 ing motion vectors to the second image” limitation of claim
 11 was taught by Sitrick.
     Because none of Prisua’s challenges to the Board’s
 analysis with respect to claim 11 have merit, the Board’s
 order that claim 11 is unpatentable for obviousness is af-
 firmed.
     Each party shall bear its own costs for this appeal and
 cross-appeal.
   AFFIRMED IN PART, REVERSED IN PART, AND
                 REMANDED
