# US 8,150,148 B2 · Method and apparatus for detecting preferred color and liquid crystal display device using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,150,148 B2 - Document ID: US8150148B2 - Status: Granted - Kind: B2 - Application number: 12/213,548 - Filed: 2008-06-20 - Published: 2009-01-08 - Granted: 2012-04-03 - Earliest claimed: 2007-06-21 - Assignees: LG Display Co., Ltd. - Inventors: Ji Young Ahn; Dong Woo Kang; Choon Woo Kim; Ji Young Yum; Byong Tae Ryu - Web page: https://patentgrep.com/patent/US8150148B2 ## CPC - G09G 5/02: characterised by the way in which colour is displayed {(details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607)} - 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 Disclosed herein are a method and apparatus for detecting a preferred color, which is capable of accurately detecting a preferred-color area with a small amount of computations, and a liquid crystal display device using the same. The method for detecting a preferred color includes comparing a hue value of an input pixel with hue reference values and detecting a first preferred-color pixel, and performing a best linear estimation (BLE) operation with respect to the first preferred-color pixel and detecting a second preferred-color pixel. ## Claims ### Claim 1 A method for detecting a preferred color, the method comprising: comparing a hue value of an input pixel with hue reference values and detecting a first preferred-color pixel; and performing a best linear estimation (BLE) operation with respect to the first preferred-color pixel and detecting a second preferred-color pixel, wherein the detecting of the second preferred-color pixel includes: calculating a preferred-color discrimination constant by a matrix product of an input matrix composed of characteristic data of the first preferred-color pixel and a weight vector matrix composed of weight vectors of the preferred color; and comparing the calculated preferred-color discrimination constant with a reference value of the preferred-color discrimination constant, detecting the pixel as the second preferred-color pixel if the preferred-color discrimination constant is included in a range of the reference value of the preferred-color discrimination constant, and detecting the pixel as the non-preferred-color pixel if the preferred-color discrimination constant is not included in the range of the reference value of the preferred-color discrimination constant. ### Claim 2 (depends on 1) The method according to claim 1, further comprising, before the detecting of the first preferred-color pixel, converting R, G and B data of the input pixel into a light (L) data and a and b color difference data into a color coordinate; and calculating the hue value h and a chroma value c of the pixel using the a and b color difference data. ### Claim 3 (depends on 2) The method according to claim 2, wherein the detecting of the first preferred-color pixel comprises comparing the hue value of the input pixel with the hue reference values which are previously set according to preferred colors, detecting the pixel as the first preferred-color pixel if the hue value is included in a hue reference value range of a preferred color, and detecting the pixel as a non-preferred-color pixel if the hue value is not included in any hue reference value range. ### Claim 4 (depends on 1) The method according to claim 1, wherein the characteristic data of the pixel includes L, a, b, c, h, R, G and B and the weight vector matrix is composed of the weight vectors of the characteristic data. ### Claim 5 (depends on 1) The method according to claim 1, wherein the detecting of the second preferred-color pixel is selectively performed according to the preferred colors. ### Claim 6 (depends on 5) The method according to claim 5, wherein the detecting of the second preferred-color pixel is performed only with respect to the pixels which are detected as the skin-color pixels in the detecting of the first preferred-color pixel. ### Claim 7 (depends on 1) The method according to claim 1, further comprising previously setting the hue reference values, and the weight vector matrix and the reference value of the preferred-color discrimination constant used in the BLE operation, according to the preferred colors, using preferred-color patches which are separately collected. ### Claim 8 An apparatus for detecting a preferred color, the apparatus comprising: a color coordinate converter which converts image data of an input pixel into a color coordinate; a hue/chroma calculator which calculates a hue value and a chroma value of the pixel using output data of the color coordinate converter; a first detector which compares the hue value of the input pixel with hue reference values and detects a first preferred-color pixel; and a second detector which performs a best linear estimation (BLE) operation with respect to the first preferred-color pixel and detects a second preferred-color pixel, wherein the second detector: calculates a preferred-color discrimination constant by a matrix product of an input matrix composed of characteristic data of the first preferred-color pixel and a weight vector matrix composed of weight vectors of the preferred color; compares the calculated preferred-color discrimination constant with a reference value of the preferred-color discrimination constant, outputs a second preferred-color detection signal if the preferred-color discrimination constant is included in a range of the reference value of the preferred-color discrimination constant, and outputs the non-preferred-color detection signal if the preferred-color discrimination constant is not included in the range of the reference value of the preferred-color discrimination constant. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein the first detector compares the hue value of the input pixel with the hue reference values which are previously set according to preferred colors, outputs a first preferred-color detection signal if the hue value is included in a hue reference value range of a preferred color, and outputs a non-preferred-color detection signal if the hue value is not included in any hue reference value range. ### Claim 10 (depends on 8) The apparatus according to claim 8, wherein the second detector outputs the second preferred-color detection signal or the non-preferred-color detection signal and outputs at least a portion of the characteristic data of the pixel. ### Claim 11 (depends on 10) The apparatus according to claim 10, wherein the second detector performs the BLE operation only with respect to the pixels which are detected as the skin-color pixels by the first detector. ### Claim 12 (depends on 8) The apparatus according to claim 8, wherein the hue reference values, and the weight vector matrix and the reference value of the preferred-color discrimination constant used in the BLE operation are previously set and stored according to the preferred colors. ### Claim 13 (depends on 8, 9, 10, 11, 12) A liquid crystal display device comprising: a preferred-color detector using the apparatus for detecting the preferred color according to any one of claims 8, 9 and 10 to 12; a preferred-color corrector which corrects the preferred color of the preferred-color pixel detected by the preferred-color detector using a preferred-color reference value and does not correct the preferred color of the non-preferred-color pixel; and an image display unit which displays data output from the preferred-color corrector.