TW560176B - Color correction method - Google Patents

Abstract

A color correction method is disclosed, which is applied in an image capturing device. The method comprises the following steps: a color space conversion step to convert the first digital three-primaries into the quantitative chroma value; a chroma computation step to calculate the quantitative chroma value for obtaining the chroma comparison value; a judging step to compare the chroma comparison value and the preset value. In the computation step of correction matrix, if the chroma comparison value is lower than the preset value, the first cost function comprising the limiting condition is used to obtain the first correction matrix. If the chroma comparison value is higher than the preset value, the second cost function without the limiting condition is used to obtain the second correction matrix. Then, the first correction matrix or the second correction matrix is multiplied by the first digitized three-primaries, so as to obtain the second digitized three-primaries and output the same.

Description

560176 Printed by Shellfish Consumer Cooperative, Central Standards Bureau, Ministry of Economic Affairs, 8366twf.doc / 009 B7 V. Description of the Invention (/) The present invention relates to a method for chroma correction, and in particular, to the color capture of an image capture device Correction method. The so-called image capture device is a digital camera (Digital Sdll Camera), a color scanner, and a digital video camera (Digital Video Camcoder) that are quite popular today. Through the development of color imaging technology and the Internet in the past ten years, the exchange of color images has become very common. Even individuals can connect different color imaging devices together through personal computers. In terms of capture and generation. Speed and resolution are constantly increasing, but because of the enhancement of the front-end technology of these images, the post-position technology is ignored, so that the chroma of the image output is still not progress. Please refer to Figure 1 and Figure 2 for reference. Figure 1 shows the components commonly used in general image capture devices, including Charge-Coupled Device (CCD) 101. Analog / A digital converter (Analog / Digital Converter; abbreviated as A / D Converter) 102, an output device 108, and the most important heart ... processing unit 104 on the image capture device. The flowchart shown in FIG. 2 is a part of the steps of the image capture device in processing the captured image. When the charge-coupled device 101 captures an image into pixels, it will convert the captured photons into analog signals and enlarge them (step s200), and the analog / digital converter 102 will be in step s202. The analog signal is converted into a digital signal, so that the subsequent processing unit 104 performs the color signal interpolation of step s204 on the digital signal and the white balance of step s206 (white. This paper applies the Chinese national standard (CNS) ) 8 4 specifications (210X297 gong) 83. 3. 10,000 r4J5 ^ — (Please read the note on the back before filling out this page) Order printed by the Central Standards Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperatives 560176 8366twf.doc / 009 A7 B7 5. Invention description (V) balance) and chroma correction (c0l0r correction) in step S208. Among them, chroma correction uses a 3 * 3 correction matrix to estimate the chromatic adaptation effect. It is an important part of people's sight of color, but some processing units 104 do not even have a color correction mechanism designed in them, such as Zoran and TI (Texas Instruments), or only for low chroma pixels, because the designer assumes that the chroma error presented by the pixel is within the acceptable range of the average person at the time of design. So far, in addition to speed, texture is also very important. Being able to adjust the accuracy of chroma to the highest level will be an important issue in the future. In view of this, the present invention proposes a method for chroma correction, which was published on July 17, 1990 in the master ’s thesis of the National Taiwan University Information Engineering Research Institute. The name is "Color characteristics and correction of digital cameras" ( Colorimetric Characterization for Digital Still Camera), whose purpose is to improve the chroma accuracy of output pixels, whether it is low or high chroma pixels, without the need to waste extra hardware costs. This method for chroma correction is applicable to image capture devices, and its steps include: a color space conversion step, a chroma calculation step, a judgment step, a correction matrix calculation step, and a second digitized three primary color acquisition step. Among them, the above steps are processed and executed by the processing unit 104 in the figure, and these steps are stored in the storage unit 106 in the form of a code. The color space conversion step is used to convert the first digitized three primary colors into chroma quantization 値, and the chroma calculation step is used to calculate chroma quantization 値 'to obtain the chroma comparison 値, this chroma comparison 値It is in the judgment step 4. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm ^ '83. 3 10,000 --- T ——: _! Installed · ------ order ----- ^ Line (please read the note on the back before filling this page) Printed by Shelley Consumer Cooperative of the Bureau of Standards and Loss of Standards of the Ministry of Economic Affairs 560176 8 3 66twf. Doc / 0 〇9 A7 B7 5. In the description of the invention (^) To compare with the preset 値. In a correction matrix calculation step, if the chroma comparison 値 is lower than the preset 値, then use the first cost function containing constraints to obtain the first correction matrix, if the chroma is 値 higher In the preset value, a second cost function is used without restriction to obtain a second correction matrix. Then, in the second digitizing three primary color obtaining step, the end-view chroma is relatively lower or higher than the preset value. A correction matrix or a second correction matrix, multiplied by the first digitized three primary colors to get The second digitizes the three primary colors and outputs them. The present invention also proposes a method for chroma correction. The following steps are processed and executed by the processing unit 104 in FIG. 1, and these steps are stored in the form of code in The storage unit 106. The steps include: decomposing the cost function 5 = into complex = 1 = several sub cost functions, which are the first sub cost function magic = text (< 2), the second / = 1 sub cost function magic And the third sub-cost functions =: ((< 2), where »= 1 1 = 1 L *, a *, b * are the first color space conversion functions. Then, these sub-cost functions are differentiated separately, The second color space conversion function X, Y, Z is obtained, and then through a relationship between the first color space conversion function and the second color space conversion function, one of the second color space conversion functions is obtained. An output matrix is operated to obtain the digitized three primary colors and further output the digitized three primary colors. In summary, the present invention can use two correction matrices to select the most suitable correction matrix for the calculated chroma comparison. Get the best degree of chroma. 5 (Please read the note on the back before filling this page) • The size of the paper is applicable to the Chinese National Standard (CNS) A4 (210X297 mm) 83. 3. 10,000 560176 8366twf .doc / 009 A7 _B7_ V. Description of the invention (today) In addition, a cost function used to calculate the correction matrix can also be decomposed into 3 sub-cost functions, because the original cost function has 3 conversion functions. Make one of them be affected by the other two functions in the calculation, and reduce the accuracy of the chroma, so that each sub-cost function can only be calculated for one conversion function, and then use the relationship between the two color space conversion functions. To get the three primary colors of the pixel output. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments in detail with the accompanying drawings as follows: Brief description of the drawings: FIG. 1 Shows an internal block diagram of one of the image capture devices that is known; Figure 2 shows a flowchart of the processing steps after image capture that is known about Figure 1; Figure 3 shows the knowledge One schematic diagram of a single charge-coupled element capturing photons to form a pixel; and FIG. 4 shows a flowchart of the chroma correction process of the present invention; and the print by the Bayer Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs ^ (Please (Please read the note on the back before filling in this page.) Figure 5 shows another flowchart of the chroma correction processing steps of the present invention. Symbol description 100: image capture device 101: charge-coupled device 102: analog / digital converter This paper size applies to China National Standard (CNS) A4 specification (210X297 mm) 83. 3. 10,000 560176 8366twf. ς ^ (c / 〇〇9 A7 B7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of Invention (Cj) 104: Processing unit 106: Storage unit 108: Output device 110: External display device steps s200 to Step S208 is one of the known processing steps. Steps s400 to S416 are one of the preferred embodiments of the present invention. Processing steps S500 to s508 are one of the other preferred embodiments of the present invention. Please refer to Figure 1 and Figure 2 for a description of the image processing device and processing flow of the general image capture device. Figure 1 shows the image capture device The device includes a charge coupled device 101, an analog / digital converter 102, a processing unit 104, a storage unit 106, and an output device 108. The image capturing device 100 herein may be a digital still camera (Digital Still Camer a; DSC for short) or a scanner. After this type of image capture device captures image data, it will transmit the processed image to an external display device 11 connected to it through an internal processing flow. This external display device The image device Π〇 can be any device that can display images, such as the current TV screen or computer screen, etc. The flowchart shown in Figure 2 is the internal processing of the captured image by the image capture device 100 Part of the steps 'that is, when the charge-coupled device 101 captures an image into pixels' will process the captured photons 7 _ This paper size (CNS) A4 secret (210X297 mm) 83. 3. 10,000- ------ ^ 装 — (Please read the notes on the back before filling out this page) Order-Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 560176 8366twf.doc / 009 A7 _B7 V. Description of the Invention (込) The analog signal is amplified and amplified (step s200), and the analog / digital converter 102 converts the analog signal to a digital signal in step S202 to facilitate subsequent processing units 104, such as a digital signal processor (Digitai Signal Processor; simple (Referred to as DSP), the digital signal is subjected to the color signal interpolation process of step S204, the white balance of step s206 and the color correction of step s208. Among them, if the image capture device 100 Is a scanner, the charge-coupled device 101 can be a device with at least three groups of scan lines, so that the so-called color signal internal difference processing is not required, but if it is a charge-coupled element in a digital camera, it may be In Figure 3, there is a single charge-coupled element. In a single square, there are several small squares that capture images to form pixels. One pixel is responsible for a channel, that is, one pixel is responsible for capturing only one of the three primary colors. Therefore, it is necessary to perform color signal internal difference processing to obtain the signals of the other two colors. Taking the image data captured by the charge-coupled element in FIG. 3 as an example, when (row, column) is (1,1) pixels, The captured primary color data is G, and the surrounding pixels, that is, the pixels of (1, 2) and (2, 1) (row, column) are used to capture the primary color data. Get. The so-called white balance processing is to simulate the human eye's identification of white color under different ambient lighting. White color will be used as the standard, and other colors will adopt the same identification method. For example, assuming that the pixel in Figure 3 (row, column) is (1, 0) is a white pixel, then multiply its known R, G, and B primary colors by a constant, so that the white color output after white balance processing is 1: 8 ------- Package-(Please read the note on the back before filling in this page) ▼ The size of the paper is applicable to China National Standard (CNS) 8-4 (210X29 * 7mm) 83. 3. 10,000 Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 560176 8366twf.doc / 009 8 7 ___ B7 ___ V. Description of the invention (A) That is: Rw * constant r = l;

Gw * constant g = 1; and Bw * constant b = 1. Among them, w refers to the white color, and except for the digitized three primary colors (R ', G' 'B') of the white color, the output 値 is 1, and other colors multiplied by these constants will have different 値 outputs. The above refers to the processing of the front-end job on the pixel color by the processing unit 104, and then the chroma correction job of the back-end is performed. For general chroma correction operations, the digitized three primary colors (R ', G', B ') after white balance are multiplied by a 3 * 3 correction matrix M, which is calculated by a cost function containing constraints, to obtain digitization. Three primary colors (R ", G", B ,,). This 3 * 3 correction matrix M is obtained from the cost function containing the constraints. This cost function is a cost function for calculating the least square error. It is derived from two color space conversion functions, which are linear least-square solutions. CIEXYZ of squares solution) and CIELAB of nonlinear least-squares solution. First, suppose that a charge-coupled element can handle n color patches, and U, · = (where, α · (, Inverse ·) is the exposure value of the ^ th small square (exposure value), V, = (foot, r "Z, ·) is the corresponding CIEXYZ tristimulus value (tristimulus value). The optimization correction matrix including the constraint conditions is from M; U, · s V, · and the square of the error is the smallest 値 2 19 This paper size applies to the Chinese National Standard (CNS) A4 specification (210X297 mm) 83. 3. 10,000 ___ * — I: ― (please read the note on the back and fill in the page first)-Order 560 176 8 3 6 6twf. Doc / 0 0 9 A7 B7

V. Description of the invention ($) Second, when all the color differences are detected, it is found that the chromaticity of all colors is based on the CIELAB color space conversion function. The general formula is ΔΤ2 + Δα * 2 + ΔZ ^ 2. It can be derived from the above: dLV 3LV ^ / 3Y XdZ (ΑΙ * ”Αα :, Αί? :) ί Order:

dY dbV db, / / dX / dY

△ Z,

azy azy / dX / dY da {/ da, // dX / dYsty dty / dX / dY / dZ

= > Δχ ,. ΔZ Λ (ν, outfit --- (please read the note on the back before filling this page), where J is called Newton-Raphson matrix. In summary, you can get general without restrictions Conditional error squared cost function is: I έ (from: 2 +) = Σ Wvr.) R W brother-dove,)] ί = 1 j = 1 and in order to get the smallest squared error, the chroma accuracy When it comes to the highest, it must be obtained to get = ", from which the best 1 = 2 = 1 best correction matrix. However, in order to make the white color that has been subjected to the white balance processing previously, the digitized three primary colors (R ", G", B ") can still be maintained after the output is 1, so the general correction matrix M must be used for this; To make a modification, add a restriction condition that the obtained correction matrix M must meet the following conditions c: m \\ + m \ 2 = ^ white m2X + / T? 22 + w23 = Ywhite ιη3] + m32 + = ^ Whue 10 This paper size applies to China National Standard (CNS) A4 (210X297 mm) Order ▼ line-Printed by Shellfish Consumer Cooperative, Central Standards Bureau, Ministry of Economic Affairs 83. 3. 10,000 560176 8366twf.doc / 009 A7 B7 V. Invention Explanation (qi) where / = 1, 2, 3, v = 1, 2, 3, and U is (1.0, 1 · 0, 1 · 0) Γ, and the better inversion matrix M must conform to MU = ( / _ >, y_7e, Zw / n.ie) r. Then, let b, y · = 1, 2, 3 be Lagrange multipliers, so the error squared by the following formula can be used to obtain the correction matrix M with constraints: S ^ ± [jX \ t -MU,) f [^ (γ -MU,.)] ^ 2 ^ K -l) 7 = 1; = 1 where is the yth / column yth row element of the correction matrix M, With a widely adopted strategy, the cost function S versus the correction matrix A / When the first derivative is equal to 0, the best solution of the correction matrix M with restricted conditions can be obtained: That is: (Please read the note on the back before filling this page)

dM + 22X, MU, Uf-2

Factory 1 Λ 3) Λ Α2 λ λλλ I I 0 = >

Λ Λ 13 Λ Λ λ I Although the above method can be used to maintain the state of white color after output is 1, it also has the best correction matrix for grayscale colors, but for other high-chroma colors But it will not improve its chroma accuracy. Printed by the Central Bureau of Standards, Ministry of Economic Affairs and Consumer Cooperatives is a method for chroma correction based on the present invention, which not only improves the accuracy of gray-scale colors, but also improves the accuracy of high-chroma colors. Please refer to FIG. 1 and FIG. 3, which cannot be drawn is a method for chroma correction according to a preferred embodiment of the present invention. This method is applicable to the image capture device 100, and the image capture device 100 It contains a processing unit 104 for processing the three primary colors (R, G, B,) and a storage unit 106 connected to the processing unit 104. The steps described below are stored in a code manner at 83.3. 1〇, 〇〇〇 This paper size applies to China's National Mou (CNS) A4 grid (210X297 mm) 5 Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 560176 8366twf.doc / 009 B7 Description of the invention (v〇) Storage unit 106, so that the processing unit 104 can use these codes to process the digitized three primary colors (R ', G', B ') into the digitized three primary colors (R ,,, G ", B") for output to an external display.像 装置 110。 The device 110. The method for chroma correction includes: the color space conversion step of step S400, which first converts the three primary colors (R, G, B,) into chroma quantization, that is, digitizes the three primary colors (R, G, B, ) Use some algorithms to convert to numbers that can be used for chroma measurement, for example, L * a * b * conversion method or Ycbcr (売 gradation chroma b chroma r; English: luminous, chroma b, chroma r ) Conversion method, as a conversion algorithm, in which the color scales 値 a * and b * obtained by the L * a * b * conversion method are used. Its operation cost will be higher than the Cr * and Cb * converted by the YCbCr conversion method, but the obtained chroma accuracy is also relatively high. Next, the chroma calculation step of step s402 is to calculate the chroma quantization 値 obtained after conversion to obtain a chroma comparison 値 T, where the chroma comparison 値 T = a * 2 + b * 2, or chroma Degree comparison 値 T = Cr * 2 + Cb * 2. In the following judgment step of step s402, the chroma comparison 値 T is compared with a preset 介于 between grayscale and high color. The comparison result, if the chroma comparison 値 T is lower than the preset 値, it indicates that this is a grayscale. For the chroma color, the correction matrix calculation step of step s406 is performed, that is, the correction matrix M is obtained by using the cost function including the constraint condition C, and then the correction matrix ^^ is digitized in the second digitizing three primary color obtaining step of step s408 The three primary colors (11 ', 0', 8 ') to obtain the digitized three primary colors (R ", G", B "), and output them to the external display device 110 in step S410. Above the preset size, it indicates that this is a high-chroma color. 12 This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) ------------- tr ----- # Line (please read the note on the back before writing this page) 83. 3. 10,000 Printed by the Central Standards Bureau of the Ministry of Economic Affairs and printed by a consumer cooperative 560176 5. Description of the invention (") Color, then perform the correction matrix calculation of step S412 Step, that is, using the cost function S1 without constraints C, get The correction matrix is from 7, and then in the second digitizing three primary colors obtaining step of step S414, the correction matrix is digitized from 0 to three primary colors (11 ,, (} ,,) to obtain the digitized three primary colors (11 ,, G ", B"), and output it to the external display device 11 in step S416. In this way, the grayscale color can be corrected to improve the accuracy, and the high chroma color can also be corrected to improve the accuracy. Please refer to FIG. 1 and FIG. 5, which show a method for chroma correction according to another preferred embodiment of the present invention, and also applicable to an image capture device 100, which includes an output device 108. The processing unit 104 for processing the three primary colors (R, G ', B') and the storage unit 106 connected to the processing unit 104. The method of chroma correction includes: step s500, which is used to calculate the correction matrix. The cost function without restriction C is decomposed into three sub-cost functions, namely sub-cost function = sub-cost function 1 = 1 'magic 2 = and sub-cost function magic 3 = because the original cost function »= 1» = 1 Number Magic Three conversion functions will cause one of them to be affected by the other two functions in the calculation, and the accuracy of the chroma will be reduced so that each sub-cost function is calculated for only one conversion function, where L *,?, b * is a CIELAB color space conversion function. As another color space conversion function CIEXYZ has the following relationship with the three primary colors of R, G, and B, the color space conversion function can be used. This paper scale applies the Chinese National Standard (CNS) A4 specification ( 210X297 mm) 83. 3. 10,000 (Please read the note on the back before filling in this page) • Packing. Order 560176 Printed by the Central Standards Bureau of the Ministry of Economic Affairs and Consumer Cooperatives 8 3 6 6twf. Doc / 0 0 9 A7 B7 V. Description of the Invention (Vv) The color space conversion function 値 X, γ, and Z obtained by CIEXYZ are derived from the digitized two primary colors (R ", G", B "), but because the color space is directly converted The color space conversion functions Zx, Y, and Z obtained by the function CIEXYZ are not unique, and the corresponding X, Y, and Z 値 are obtained indirectly by calculating the CIELAB color space conversion function. Therefore, in step S502, the sub-cost functions magic 1, M2, and S13 are differentiated respectively, where ^ 11 differentiates Y to obtain a color space conversion function, and magic 2 pairs X and Y to obtain a color space conversion function xa, Ya'M3 differentiates Y and Z to obtain color space conversion functions Yb and Zb. Then, in step s504, the relationship between the color space conversion function CIELAB and the color space conversion function CIEXYZ (as shown below) is used to obtain the color space conversion function X, γ, and Z: Γ = 116 / (7 / 7η) -16 a = 500 [f (X / Xn) -f (Y / Yn)] b * = 200 [f (Y / Yn) ^ f (Z / Zn)] Αω) = | (ω) 1/3 ω > 0.008856 [7.787 (ω) + 16 / ΐ16 ω < 0.008856 where '(< Λ, Z „) is a reference constant and ω is an independent variable. Then the color space conversion functions X, Υ, and Z are output. To the external development device 110, through the judgment of the external development device 110, the color space conversion functions X, Υ, and 値 are converted into r, G, and B primary colors. The color space conversion function X is multiplied by an output matrix. , Γ, ζ to obtain the digitized three primary colors (R ,,, G ", B") (step S506), and further output (step s508). 14 This paper is suitable for Zhongguanjia County (CNS) from Threat (2 offering 297 male thin) 83. 3. 10,000 —i I ——— ^ wi ϋ I ϋ ^ line (please read the note on the back before filling in the page) 560176 ° c / 〇〇 & A7 B7 V. Description of Invention (\,) " ^ In the above, although the two methods can be operated independently to make the chromaticity of each color more accurate, the two methods can also be combined to make the chromaticity of each color more accurate. The advantage of the invention is that the corrected color of grayscale or high chroma can be closer to the color of the original object, so that the chroma accuracy is more accurate. Although the present invention has been disclosed above in a preferred embodiment, it is not useful. In order to limit the present invention, anyone skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application. . -------- ί ^ -pack-(Please read the note on the back before filling in this page} -Ή-Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 15 83. 3. 10,000 copies Paper size applies to China National Standards (CNS) A4 specifications (210X297 cm)

Claims (1)

Printed by Shelley Consumer Cooperative of the Central Bureau of the Ministry of Economic Affairs 560176 A8 B8 B366twf.doc / 009 C8 D8 VI. Application for Patent Scope 1. A method for chroma correction, which is suitable for an image capture device, which contains a A processing unit of a digitized three primary colors and a storage unit connected to the processing unit. The method for chroma correction includes: a color space conversion step for converting the first digitized three primary colors into a color metric; A chroma calculation step is used to calculate the chroma measure 値 to obtain a chroma comparison 値; a judgment step is used to compare the chroma comparison 値 and a preset 値; a correction matrix calculation step, if the chroma If the comparison value is lower than the preset value, a first cost function including a restriction condition is used to obtain a first correction matrix. If the saturation value is higher than the preset value, one of the correction conditions is used. A second cost function to obtain a second correction matrix; and a second digitizing three primary color obtaining step, selecting the first correction matrix and the second correction matrix, and multiplying them The first digit of the three primary colors to give a second digit of the second of three primary colors and further output digitized three primary colors. 2. The method for chroma correction as described in item 1 of the scope of patent application, wherein the image capture device is a digital camera. 3. The method for chroma correction according to item 1 of the scope of patent application, wherein the image capturing device is a scanner. 4. The method for chroma correction according to item 1 of the scope of patent application, wherein the steps are stored in the storage unit in a code manner, so that the processing unit uses the code to digitize the first digitization. The three primary colors are processed. This paper size applies to China National Standard (CNS) A4 specification (210X297 mm) ------: -III (Please read the notes on the back before filling out this page)-Order-560 176 A8 B8 C8 D8 8366twf. doc / 009 VI. Patent Application Range 5. The method of chroma correction as described in item 1 of the patent application range, where ψ the first cost function and the second cost function are cost functions for calculating the least square error . 6. A method for chroma correction, which is applicable to an image capture device, which includes an output device, a processing unit that processes a first digitized three primary colors, and a storage unit connected to the processing unit. The chroma correction The method includes: decomposing a cost function magic = $ (ΔZ; 2 + Δα: 2 + Δ6; 2) into a plurality of sub cost functions, respectively, a first sub cost function magic 1 = 1; (from 卩), a The second sub-cost 7 = 1 function ^ 12 = ί: (Δ < 2) and a third sub-cost function magic 3 = Σ (Δ < 2), where ι '= ι; = ι M, b * are the first A color space conversion function; differentiating the sub-cost functions respectively to obtain a second color space conversion function X, Y, Z; via one of the first color space conversion function and the second color space conversion function A relational expression is used to obtain the second color space conversion function; and the second color space conversion function is calculated with an output matrix to obtain a second digitized three primary color and further output the second digitized three primary color. 7. The method for chroma correction as described in item 6 of the scope of patent application, wherein the relationship is: L, ii6 / (r / r ”)-16 a =: 500 [f {X / Xn) -f { Y! Yn)] 17 This paper size applies to China National Standards (CNS) Α4 size (210 × 297 mm)-installed-(Please read the precautions on the back before filling out this page)-Order the Central Bureau of Standards, Ministry of Economic Affairs Printed by Shelley Consumer Cooperative 560176 A8 B8 C8 D8 b ^ 200 [f (Y / Yn) -f (Z / Zn)] _ \ (ω)] / 3 ω > 0.008856 _ · ω < `` 8366twf.doc / 009 Patent application scope. 787⑹ + 16/116 where '(1, dagger) is a reference constant and ω is an independent variable. 8. The chroma correction method described in item 6 of the patent application scope, where The output matrix will be different according to an external display device connected to the output device. 9. The method of chroma correction as described in item 8 of the patent application scope, wherein the external display device may be a computer screen. 10. The chroma correction method as described in item 8 of the scope of patent application, wherein the external display device may be a television screen. · (Please read the note on the back before filling in this page ) Printed by Shellfish Consumer Cooperatives, Central Bureau of Standards, Ministry of Economic Affairs 18 This paper size applies to China National Standard (CNS) Α4 specification (210 × 297 mm)