# US 10,873,684 B2 · Video display apparatus and video display method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,684 B2 - Document ID: US10873684B2 - Status: Granted - Kind: B2 - Application number: 16/332,738 - Filed: 2018-02-26 - Published: 2019-12-19 - Granted: 2020-12-22 - Earliest claimed: 2017-07-14 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Intellectual Property Management Co., Ltd. - Inventors: Masayuki Kozuka; Masaya Yamamoto; Yoshiichiro Kashiwagi; Toshiroh Nishio; Kazuhiko Kouno; Hiroshi Yahata; Takeshi Hirota; Yoshihiro Mori - Web page: https://patentgrep.com/patent/US10873684B2 ## CPC - H04N 5/20: Circuitry for controlling amplitude response - H04N 5/202: Gamma control (circuits for controlling camera response irrespective of the scene brightness H04N23/82) - H04N 9/646: {for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters} - H04N 9/77: Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase (circuits for matrixing H04N9/67) - H04N 21/431: Generation of visual interfaces {for content selection or interaction}; Content or additional data rendering - H04N 21/47: End-user applications - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A video display apparatus includes: a tone mapping processor that performs a tone mapping process of converting a luminance of a video by using conversion characteristics according to a maximum luminance of the video; and a display that displays the video that has undergone the tone mapping process. The tone mapping processor switches between a first tone mapping process of dynamically changing the conversion characteristics according to a time-depend change in the maximum luminance of the video and a second tone mapping process that is performed using constant conversion characteristics irrespective of the time-depend change in the maximum luminance of the video. When the tone mapping process used is switched from the second tone mapping process to the first tone mapping process, the conversion characteristics used is changed gradually or stepwise from the constant conversion characteristics to dynamically changing conversion characteristics over a plurality of frames. ## Claims ### Claim 1 A video display apparatus, comprising: a tone mapping processor that performs a tone mapping process of converting a luminance of a video by using conversion characteristics according to a maximum luminance of the video; and a display that displays the video that has undergone the tone mapping process, wherein the tone mapping processor switches between a first tone mapping process of dynamically changing the conversion characteristics according to a time-dependent change in the maximum luminance of the video and a second tone mapping process that is performed using constant conversion characteristics irrespective of the change in the maximum luminance of the video, and when the tone mapping process used is switched from the second tone mapping process to the first tone mapping process, the conversion characteristics used is changed gradually or stepwise from the constant conversion characteristics to dynamically changing conversion characteristics over a plurality of frames. ### Claim 2 (depends on 1) The video display apparatus according to claim 1, wherein the tone mapping processor performs the first tone mapping process when the video does not contain graphics, and performs the second tone mapping process when the video contains graphics. ### Claim 3 (depends on 2) The video display apparatus according to claim 2, wherein, in the second tone mapping process, with respect to a luminance greater than or equal to a border luminance level, the tone mapping processor dynamically changes the conversion characteristics according to the time-dependent change in the maximum luminance of the video, and with respect to a luminance less than the border luminance level, the tone mapping processor uses the constant conversion characteristics irrespective of the change in the maximum luminance of the video. ### Claim 4 (depends on 1) The video display apparatus according to claim 1, wherein the tone mapping processor determines which of the first tone mapping process and the second tone mapping process is to be performed according to a first flag that indicates which of the first tone mapping process and the second tone mapping process is to be performed. ### Claim 5 (depends on 4) The video display apparatus according to claim 4, wherein the first flag includes a second flag that indicates whether or not the video contains subtitles and a third flag that indicates whether or not the video contains a menu. ### Claim 6 (depends on 4) The video display apparatus according to claim 4, wherein the first flag indicates a subtitles display period, which is a time period during which the subtitles are intermittently displayed, and a subtitles non-display period during which the subtitles are not displayed for a predetermined length of time or longer, and the tone mapping processor performs the second tone mapping process during the subtitles display period, and performs the first tone mapping process during the subtitles non-display period. ### Claim 7 (depends on 1) The video display apparatus according to claim 1, wherein, when switching from the first tone mapping process to the second tone mapping process, the tone mapping processor continuously uses the conversion characteristics used immediately before the switching in the second tone mapping process. ### Claim 8 A video display method in a video display apparatus, the video display method comprising: performing a tone mapping process of converting a luminance of a video by using conversion characteristics according to a maximum luminance of the video; and displaying the video that has undergone the tone mapping process, wherein, in the tone mapping process, switching is performed between a first tone mapping process of dynamically changing the conversion characteristics according to a time-dependent change in the maximum luminance of the video and a second tone mapping process that is performed using constant conversion characteristics irrespective of the change in the maximum luminance of the video, and when the tone mapping process used is switched from the second tone mapping process to the first tone mapping process, the conversion characteristics used is changed gradually or stepwise from the constant conversion characteristics to dynamically changing conversion characteristics over a plurality of frames.