# US 5,351,135 A · Managing letterbox signals with logos > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,351,135 A - Document ID: US5351135A - Status: Granted - Kind: A - Application number: 08/057,026 - Filed: 1993-05-05 - Granted: 1994-09-27 - Earliest claimed: 1990-06-01 - Assignees: Thomson Consumer Electronics, Inc. - Inventors: Timothy W. Saeger - Web page: https://patentgrep.com/patent/US5351135A ## CPC - H04N 21/4884: {for displaying subtitles} - H04N 3/223: Controlling dimensions (by maintaining the cathode-ray tube high voltage constant H04N3/185) - H04N 3/27: Circuits special to multi-standard receivers - H04N 5/45: Picture in picture {, e.g. displaying simultaneously another television channel in a region of the screen} - H04N 7/007: {Systems with supplementary picture signal insertion during a portion of the active part of a television signal, e.g. during top and bottom lines in a HDTV letter-box system} - H04N 7/01: Conversion of standards {, e.g. involving analogue television standards or digital television standards processed at pixel level} - H04N 7/0105: {using a storage device with different write and read speed} - H04N 7/0122: {the input and the output signals having different aspect ratios} - H04N 9/641: {Multi-purpose receivers, e.g. for auxiliary information (H04N9/642 takes precedence)} - H04N 21/47: End-user applications - H04N 9/7925: {for more than one standard} - Y10S 348/913: Letterbox, e.g. display 16:9 aspect ratio image on 4:3 screen - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A video display control system comprises: a video display having a wide format display ratio; a letterbox detector for sampling video information in pictures represented by input video signals having a letterbox format and generating a control signal for enlarging the pictures for substantially filling the video display means with active video, the letterbox format pictures sometimes having auxiliary information disposed in a border area; and, a circuit for preventing the letterbox detector from sampling the video information in any portion of the border area in which the auxiliary information can be expected to be disposed, when present. In the case of logos, which are generally disposed near or at the right side of the lower border, a horizontal sampling range will exclude the right side of each horizontal line. ## Claims ### Claim 1 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area; and, means for controlling operation of said letterbox processor to ignore a certain type of said auxiliary information when present. ### Claim 2 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area, a first type of said auxiliary information disposed in a first horizontal range of said border area and a second type of said auxiliary information disposed in a second horizontal range of said border area, at least partly exclusive of said first range; and, means for controlling operation of said letterbox processor being controlled to ignore said first type of said auxiliary information when present. ### Claim 3 (depends on 2) The system of claim 2, wherein said controlling means inhibits a determination of whether said input video signal has said letterbox format responsive to said first type of said auxiliary information. ### Claim 4 (depends on 2) The system of claim 2, wherein said controlling means enables a determination of whether said input video signal has said letterbox format only during horizontal scanning in that part of said second range at least partly exclusive of said first range. ### Claim 5 (depends on 2) The system of claim 2, wherein said means for controlling operation of said letterbox processor comprises pixel counting means for initiating a letterbox detection enable signal at a first pixel count and terminating said enable signal at a second pixel count defining a sampling range exclusive of said first horizontal range. ### Claim 6 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area; and, means for controlling operation of said letterbox processor to inhibit a determination of whether said input video signal has said letterbox format responsive to a type of said auxiliary information which is likely to be positioned, when present, in a first horizontal range not coincident with a substantial portion of a second and larger horizontal range in which another type of said auxiliary information is likely to appear, when present. ### Claim 7 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area; and, means for controlling operation of said letterbox processor to enable a determination of whether said input video signal has said letterbox formats responsive to a type of said auxiliary information which is likely to be positioned, when present, in a first horizontal range, only a small part of which may be coincident when coincident at all, with a second and smaller horizontal range, in which another type of said auxiliary information is likely to appear, when present. ### Claim 8 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area; and, pixel counting means for controlling operation of said letterbox processor to ignore a certain type of said auxiliary information, when present, by initiating a letterbox detection enable signal at a first pixel count and terminating said enable signal at a second pixel count. ### Claim 9 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox processor for determining when a picture represented by an input video signal has a letterbox format, said letterbox format picture sometimes having auxiliary information disposed in a border area; and, means for controlling operation of said letterbox processor to ignore a certain type of said auxiliary information when present, said controlling means comprising: means for generating a running pixel count; means for comparing first and second predetermined counts to said running pixel count; and, means responsive to said comparing means for generating a letterbox detection enable signal when said running pixel count is between said first and second predetermined counts. ### Claim 10 A video display control system, comprising: a video display means having a wide format display ratio; means for determining when a picture represented by an input video signal is indicative of said picture having a letterbox format in which an active video portion of said picture is positioned between upper and lower border areas, said letterbox format picture sometimes having auxiliary information positioned in different portions of said border areas; means responsive to said letterbox determining means for enlarging said picture in size to substantially fill said video display means with said active video portion when said input video signal is determined to have said letterbox format; and, means for inhibiting said determining means from responding to one type of said auxiliary information by restricting operation of said determining means to a predetermined portion of said border areas likely to exclude said one type of said auxiliary information, when present. ### Claim 11 A video display system, comprising: a video display means having a wide format display ratio; means for determining when a picture represented by an input video signal is indicative of said picture having a letterbox format in which an active video portion of said picture is positioned between upper and lower border areas, said letterbox format picture sometimes having auxiliary information positioned in different portions of said border areas; means responsive to said letterbox determining means for enlarging said picture in size to substantially fill said video display means with said active video portion when said input video signal is determined to have said letterbox format; and, means for inhibiting said determining means from responding to one type of said auxiliary information by enabling operation of said determining means in a predetermined horizontal range of each horizontal line of said input signal likely to exclude said one type of said auxiliary information, when present. ### Claim 12 (depends on 11) The system of claim 11, wherein said predetermined horizontal range is substantially horizontally centered with respect to said tested horizontal lines. ### Claim 13 (depends on 12) The system of claim 12, wherein said range extends over approximately 70% of each of said tested horizontal lines. ### Claim 14 A video display control system, comprising: a video display means having a wide format display ratio; means for determining when a picture represented, by an input video signal is indicative of said picture having a letterbox format in which an active video portion of said picture is positioned between upper and lower border areas, said letterbox format picture sometimes having auxiliary information positioned in different portions of said border areas; means responsive to said letterbox determining means for enlarging said picture in size to substantially fill said video display means with said active video portion when said input video signal is determined to have said letterbox format; and, pixel counting means for inhibiting said determining means from responding to one type of said auxiliary information by initiating a letterbox detection enable signal at a first pixel count and terminating said enable signal at a second pixel count to restrict operation of said determining means to a predetermined portion of said border areas likely to exclude said one type of said auxiliary information, when present. ### Claim 15 (depends on 14) The system of claim 14, wherein said first and second pixel counts are predetermined. ### Claim 16 A video display control system comprising: a video display means having a wide format display ratio; means for determining when a picture represented by an input video signal is indicative of said picture having a letterbox format in which an active video portion of said picture is positioned between upper and lower border areas, said letterbox format picture sometimes having auxiliary information positioned in different portions of said border areas; means responsive to said letterbox determining means for enlarging said picture in size to substantially fill said video display means with said active video portion when said input video signal is determined to have said letterbox format; and, means for inhibiting said determining means from one type of said auxiliary information by restricting operation of said determining means to a predetermined portion of said border areas likely to exclude said one type of said auxiliary information, when present, said inhibiting means comprising: means for generating a running pixel count; means for comparing first and second predetermined counts to said running pixel count; and, means responsive to said comparing means for generating a letterbox detection enable signal when said running pixel count is between said first and second predetermined counts. ### Claim 17 (depends on 16) The system of claim 16, wherein: said comparing means comprises first and second comparators, responsive to said first and second predetermined pixel counts respectively, and both responsive to said running pixel count; and, said means responsive to said comparing means comprises a flip/flop responsive to each of said comparators, for initiating said letterbox detection enable signal when said running pixel count reaches said first predetermined pixel count and terminating said enable signal when said running pixel count reaches said second predetermined pixel count. ### Claim 18 (depends on 17) The system of claim 17, wherein each of said first and second pixel counts and said running pixel count represent a fraction of an actual pixel count. ### Claim 19 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox detector for sampling video information in pictures represented by input video signals having a letterbox format and generating a control signal for enlarging said pictures for substantially filling said video display means with active video, said letterbox format pictures sometimes having auxiliary information disposed in a border area; and, means for preventing said letterbox detector from sampling said video information in any portion of said border area in which said auxiliary information can be expected to be disposed, when present. ### Claim 20 A video display control system, comprising: a video display means having a wide format display ratio; a letterbox detector for sampling video information in pictures represented by input video signals having a letterbox format and generating a control signal for enlarging said pictures for substantially filling said video display means with active video, said letterbox format pictures sometimes having auxiliary information disposed in a border area; and, means for preventing said letterbox detector from sampling said video information in any portion of said border area in which said auxiliary information can be expected to be disposed, when present, by initiating a letterbox detection enable signal at a first pixel count and terminating said enable signal at a second pixel count.