# US 8,786,627 B2 · Method for displaying video signal dithered by related masks and video display apparatus applying the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,627 B2 - Document ID: US8786627B2 - Status: Granted - Kind: B2 - Application number: 12/835,894 - Filed: 2010-07-14 - Published: 2011-06-16 - Granted: 2014-07-22 - Earliest claimed: 2009-12-10 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Ji-yong Park; Sang-kyun Im; Nam-kyun Beon - Inventors: Ji-yong Park; Sang-kyun Im; Nam-kyun Beon - Web page: https://patentgrep.com/patent/US8786627B2 ## CPC - G09G 3/2055: {the pattern being varied in time} - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - G09G 3/2059: {using error diffusion} - G09G 3/2077: {by a combination of two or more gradation control methods} - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G 2320/0666: for control of colour parameters, e.g. colour temperature - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A method for displaying a video which is dithered using related masks and a video display apparatus applying the same, the video display apparatus dithering a video signal using a first mask, performing color-processing with respect to the video signal, and dithering the color-processed video signal using a second mask which is related to the first mask. Accordingly, dithering is performed using related masks, thus preventing poor gradation of video signal. ## Claims ### Claim 1 A video display apparatus comprising: a video processor which signal-processes an input video signal; and a video output unit which displays the signal-processed video signal on a display, wherein the video processor comprises: a first dithering unit which dithers the input video signal using a first mask; a color processor which color-processes the dithered video signal output from the first dithering unit; and a second dithering unit which dithers the color-processed video signal using a second mask related to the first mask, wherein the second dithering unit uses, as the second mask, a mask determined from among a plurality of predetermined masks according to the first mask used by the first dithering unit, wherein, in response to a first predetermined mask being selected, by the first dithering unit, as the first mask, a corresponding second predetermined mask is subsequently selected, by the second dithering unit, as the second mask according to the selection of the first predetermined mask, and wherein a sum of coefficients at a location corresponding to the first mask is equal to a sum of coefficients at a location corresponding to the second mask. ### Claim 2 (depends on 1) The video display apparatus as claimed in claim 1, wherein the first mask has a same format as the second mask. ### Claim 3 (depends on 2) The video display apparatus as claimed in claim 2, wherein the second mask comprises coefficients that compensate for corresponding coefficients of the first mask. ### Claim 4 (depends on 1) The video display apparatus as claimed in claim 1, wherein the second dithering unit dithers the color-processed video signal using an error diffusion dithering scheme, and dithers the error diffusion-dithered video signal using the second mask. ### Claim 5 (depends on 1) The video display apparatus as claimed in claim 1, wherein the first dithering unit dithers the input video signal using the first mask if a bit unit of the input video signal exceeds a predetermined bit unit, and does not dither the input video signal if the bit unit of the input video signal is the predetermined bit unit. ### Claim 6 (depends on 5) The video display apparatus as claimed in claim 5, wherein the second dithering unit dithers the color-processed video signal using the second mask if a bit unit of the input video signal input to the first dithering unit exceeds the predetermined bit unit, and dithers the color-processed video signal using a third mask if the bit unit of the input video signal input to the first dithering unit is the predetermined bit unit. ### Claim 7 (depends on 6) The video display apparatus as claimed in claim 6, wherein the third mask has a format which is larger than a format of the second mask. ### Claim 8 (depends on 1) The video display apparatus as claimed in claim 1, wherein the input video signal is a video signal which is separated from a received broadcast signal or a video signal which is received from an external apparatus. ### Claim 9 A video display method, comprising: dithering a video signal using a first mask; color-processing the dithered video signal; dithering the color-processed video signal using a second mask related to the first mask; and outputting the dithered video signal, wherein the second mask is determined from among a plurality of predetermined masks according to the first mask, wherein, in response to a first predetermined mask being selected as the first mask, a corresponding second predetermined mask is subsequently selected as the second mask according to the selection of the first predetermined mask, and wherein a sum of coefficients at a location corresponding to the first mask is equal to a sum of coefficients at a location corresponding to the second mask. ### Claim 10 (depends on 9) The video display method as claimed in claim 9, wherein the outputting the dithered video signal comprises displaying the dithered video signal on a display. ### Claim 11 (depends on 9) The video display method as claimed in claim 9, wherein the first mask has a same format as the second mask. ### Claim 12 (depends on 11) The video display method as claimed in claim 11, wherein the second mask comprises coefficients that compensate for corresponding coefficients of the first mask. ### Claim 13 (depends on 9) The video display method as claimed in claim 9, wherein the dithering the color-processed video signal using the second mask comprises dithering the color-processed video signal using an error diffusion dithering scheme, and dithering the diffusion-dithered video signal using the second mask. ### Claim 14 (depends on 9) The video display method as claimed in claim 9, wherein the dithering the video signal using the first mask comprises dithering the first video signal using the first mask if a bit unit of the video signal exceeds a predetermined bit unit, and not dithering the video signal if the bit unit of the video signal is the predetermined bit unit. ### Claim 15 (depends on 14) The video display method as claimed in claim 14, wherein the dithering the color-processed video signal using the second mask comprises dithering the color-processed video signal using the second mask if a bit unit of the video signal exceeds the predetermined bit unit, and dithering the color-processed video signal using a third mask if the bit unit of the video signal is the predetermined bit unit. ### Claim 16 (depends on 15) The video display method as claimed in claim 15, wherein the third mask has a format which is larger than a format of the second mask. ### Claim 17 (depends on 9) The video display method as claimed in claim 9, wherein the video signal is a video signal which is separated from a received broadcast signal or a video signal which is received from an external apparatus. ### Claim 18 (depends on 9) A non-transitory computer readable recording medium having recorded thereon a program executable by a computer for performing the method of claim 9. ### Claim 19 A video processor comprising: a first dithering unit which dithers a video signal using a first mask; a color processor which color-processes the dithered video signal output from the first dithering unit; and a second dithering unit which dithers the color-processed video signal using a second mask related to the first mask, wherein the second dithering unit uses, as the second mask, a mask determined from among a plurality of predetermined masks according to the first mask used by the first dithering unit, wherein, in response to a first predetermined mask being selected, by the first dithering unit, as the first mask, a corresponding second predetermined mask is subsequently selected, by the second dithering unit, as the second mask according to the selection of the first predetermined mask, and wherein a sum of coefficients at a location corresponding to the first mask is equal to a sum of coefficients at a location corresponding to the second mask. ### Claim 20 (depends on 1) The video display apparatus as claimed in claim 1, wherein the plurality of predetermined masks have predetermined coefficients. ### Claim 21 (depends on 1) The video display apparatus as claimed in claim 1, wherein the first dithering unit dithers lower two bits of the video signal and the second dithering unit dithers lower two bits of the color-processed video signal.