CN101221737B - Gray scale conversion device and method - Google Patents

Abstract

The invention discloses a gray scale or gray scale conversion device, which comprises a receiving module, an encoding module and a decoding module. The receiving module is used for receiving an input image, wherein the input image has N bits of first gray scale. The encoding module is used for selectively calculating a first color gradation according to the M high bits and the T low bits of the first gray gradation, and calculating a second color gradation and a third color gradation according to the M high bits of the first gray gradation. The decoding module is used for converting the first color gradation, the second color gradation and the third color gradation into N-bit second gradation through a gray scale conversion formula.

Description

Gray scale conversion device and method

technical field

The present invention relates to a grayscale or grayscale (gray scale) conversion device and method, and in particular to a grayscale conversion that can convert the grayscale (or grayscale, Gray level) of an input image (input image) Devices and methods.

Background technique

Generally speaking, the basic function of a graphics card is to provide computer graphics display, so that the signal sent by the computer can be displayed at the correct position of the monitor. The input image to be displayed on the computer is a control signal converted into a color image through the graphics card, and after being sent to the monitor, the graphics and colors are displayed on the screen.

In the prior art, if the input image is a 10-bit image, a 10-bit dedicated graphics card is needed to change the 10-bit image into a control signal for a color image; if the input image is a 12-bit image, a 12-bit graphics card is required. 12-bit dedicated graphics card, change the 12-bit image to the control signal of the color image; and so on. However, due to the high price of a dedicated graphics card, the overall cost of the computer will be increased.

Therefore, the object of the present invention is to provide a grayscale conversion device and method to solve the above problems.

Contents of the invention

An object of the present invention is to provide a gray scale conversion device and method, no matter how many bits (such as 8 bits, 10 bits, 12 bits, etc.) the gray scale of an input image can be converted through a general graphics card.

According to a preferred embodiment, the grayscale conversion device of the present invention includes a receiving module, an encoding module and a decoding module. The receiving module is used for receiving an input image, wherein the input image has N-bit first gray levels (Gray level), and N is a natural number. The encoding module is used to selectively calculate the first color gradation according to the M high bits and T low bits of the first gray scale, and calculate the second color gradation and the third color gradation according to the M high bits of the first gray scale degree, where M and T are a natural number, and M plus T is equal to N. The decoding module converts the first color gradation, the second color gradation, and the third color gradation into N-bit second grayscales through a grayscale conversion formula.

In this embodiment, the first color gradation, the second color gradation, and the third color gradation calculated by the decoding module can be converted into control signals via a general graphics card, and then sent to the decoding module for conversion. is the N-bit second grayscale. After that, the input image can be displayed on the display device with N-bit grayscale.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings.

Description of drawings

FIG. 1 is a functional block diagram showing electronic equipment to which the grayscale conversion device of the present invention is applied.

FIG. 2 is a flowchart of a grayscale conversion method according to a preferred embodiment of the present invention.

Detailed ways

The invention provides a device and method for converting the gray scale of an input image in an electronic device (such as a computer). No matter how many bits the grayscale of the input image is (such as 8 bits, 10 bits, 12 bits, etc.), it can be converted through a general graphics card.

Please refer to FIG. 1 . FIG. 1 is a functional block diagram illustrating an electronic device 1 applying a grayscale converting device 10 of the present invention. The electronic device 1 includes a gray scale conversion device 10 , a graphic card 12 , a digital video interface (Digital Video Interface, DVI) 14 and a display device 16 . The grayscale conversion device 10 of the present invention includes a receiving module 100 , an encoding module 102 and a decoding module 104 . The encoding module 102 includes a judging unit 1020 . In particular, any type of graphics card and digital video interface is suitable for use with the present invention.

As shown in FIG. 1 , the receiving module 100 is configured to receive an input image Img, wherein the input image Img has N-bit gray scales, and N is a natural number. In this embodiment, the grayscale of the input image Img is set to be 10 bits for illustration, that is, N=10.

The coding module 102 is used to selectively calculate a first color gradation according to the M high bits and T low bits of the gray scale of the input image Img, and calculate a second color gradation and a third color according to the M high bits degree, wherein M and T are a natural number, and M plus T is equal to N. In actual application, the first color gradation may be blue gradation, the second color gradation may be green gradation, and the third color gradation may be red gradation; the first color gradation may be red gradation, The second color gradation can be a blue gradation, and the third color gradation can be a green gradation; or the first color gradation can be a green gradation, the second color gradation can be a red gradation, and the third color gradation can be a green gradation. The color gradation may be blue gradation. In this embodiment, the first color gradation is set as red gradation, the second color gradation is blue gradation, and the third color gradation is green gradation for illustration.

In addition, since general image processing uses 8 bits to present the color gradation, therefore, in this embodiment, the first 8 bits of the 10-bit gray scale of the input image Img are set as high bits (that is, M=8), and The last 2 bits are low bits (ie T=2).

When the input image Img is sent to the encoding module 102 via the receiving module, the judging unit 1020 will judge whether the gray scale Y ₁ of the input image Img is smaller than a threshold (Threshold) 2 ^N-1 , and if so, calculate the gray scale according to the following formula 1 Y ₃ , red gradation C ₁ , blue gradation C ₂ , and green gradation C ₃ , if not, calculate gray scale Y ₄ , red gradation C ₁ , and blue gradation C ₂ according to the following formula 2 and shades of green C ₃ . In this embodiment, N=10, and the threshold value is 2 ⁹ =512. Formula one: $\left\{\begin{array}{c}{Y}_3=Y_1*\frac{(2^{N-1}-1)-x_1}{2^{N-1}}\\ C_1=Y_3\left[m\right]+Y_3\left[T\right]\\ C_2=Y_3\left[m\right]\\ C_3=Y_3\left[m\right]\end{array}\right.$ Formula two: $\left\{\begin{array}{c}{Y}_4=(Y_1-2^{N-1})*\frac{(2^{N-1}-1)-x_2}{2^{N-1}}+1+2^{N-1}\\ C_1=Y_4\left[m\right]-\left({2^{N-m}-1-Y}_4\left[T\right]\right)\\ C_2=Y_4\left[m\right]\\ C_3=Y_4\left[m\right]\end{array}\right..$

In the above formula 1 and formula 2, X ₁ is a first predetermined value, X ₂ is a second predetermined value, X ₁ plus X ₂ is equal to 2 ^(NM) -1, Y ₃ [M] represents the grayscale Y The M high bits of ₃ , Y ₃ [T] represent the T low bits of gray scale Y ₃ , Y ₄ [M] represent the M high bits of the fourth gray scale, and Y ₄ [T] represent the fourth gray scale The T low bits of the degree. In this embodiment, N=10, M=8, T=2, set X ₁ =2, X ₂ =1, then Formula 1 and Formula 2 can be expressed as follows. Formula one: $\left\{\begin{array}{c}{Y}_3=Y_1*\frac{511-2}{511}\\ C_1=Y_3[9:2]+Y_3[1:0]\\ C_2=Y_3[9:2]\\ C_3=Y_3[9:2]\end{array}\right.$ Formula two: $\left\{\begin{array}{c}{Y}_4=(Y_1-512)*\frac{511-1}{511}+1+512\\ C_1=Y_4[9:2]-\left({3-Y}_4[1:0]\right)\\ C_2=Y_4[9:2]\\ C_3=Y_4[9:2]\end{array}\right..$

For example, if the grayscale Y ₁ of the input image Img is 511, it is expressed as [0 1 1 1 1 1 1 1 1] with 10 bits. Since Y ₁ (511) is less than 512, the judging unit 1020 will calculate the gray scale Y ₃ = 509 (if not divisible, take an integer) according to formula 1, expressed as [0 1 1 1 1 1 1 1 0 1 in 10 bits ]; red scale C ₁ is 127 (expressed as [0 1 1 1 1 1 1] in 8 bits) plus 1 (expressed in 8 bits as [0 0 0 0 0 0 0 1]) is equal to 128; blue The gradation C ₂ is 127 (expressed as [0 1 1 1 1 1 1 1] in 8 bits); the green gradation C ₃ is 127 (expressed in 8 bits as [0 1 11 1 1 1 1]).

Afterwards, the red gradation C ₁ , the blue gradation C ₂ and the green gradation C ₃ are transmitted to the decoding module 104 via the graphic card 12 and the digital video interface 14 . The decoding module 104 converts the red level C ₁ , the blue level C ₂ and the green level C ₃ into a 10-bit gray level Y ₂ through a gray level conversion formula. In this embodiment, the grayscale conversion formula is represented by the following formula three. Formula 3: Y ₂ =(a*C ₁ +b*C ₂ +c*C ₃ )*2 ^NM

b加c等于

在此实施例中，N＝10，M＝8，设定b＝0.586，c＝0.164，则公式三可表示如下。公式三：Y₂＝(0.25*C₁+0.586*C₂+0.164*C₃)*4In the above formula 3, a is equal to

b plus c equals

In this embodiment, N=10, M=8, set b=0.586, c=0.164, then formula 3 can be expressed as follows. Formula 3: Y ₂ =(0.25*C ₁ +0.586*C ₂ +0.164*C ₃ )*4

Therefore, if the red level C ₁ is 128, the blue level C ₂ is 127, and the green level C ₃ is 127, then the gray level Y ₂ =509.

Afterwards, the input image Img can be displayed on the display device 16 with 10-bit grayscale Y ₂ (509).

Please refer to FIG. 2 . FIG. 2 is a flowchart of a grayscale conversion method according to a preferred embodiment of the present invention. Please also refer to FIG. 1 , according to the above-mentioned embodiment, the grayscale conversion method of the present invention includes the following steps. Firstly, step S100 is executed to receive an input image Img, wherein the input image Img has N-bit grayscale. Next, execute step S102, selectively calculate the first color gradation according to the M high bits and T low bits of the gray scale of the input image Img, and calculate the second color gradation and the third color gradation according to the M high bits . Afterwards, step S104 is executed to convert the first color gradation, the second color gradation, and the third color gradation into N-bit grayscales by using a grayscale conversion formula. The detailed working principle is as described above, and will not be repeated here.

Compared with the prior art, the red gradation, blue gradation and green gradation calculated by the encoding module of the gray scale conversion device of the present invention can be converted into control signals via a general graphics card, and then sent to the decoding module. It is further converted into a grayscale with the same number of bits as the original grayscale. This eliminates the need for a dedicated graphics card, reducing costs.

Through the above detailed description of the preferred specific embodiments, it is hoped that the characteristics and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred specific embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the claimed invention. Therefore, the scope of the claimed patent scope of the present invention should be interpreted in the broadest way based on the above description, so as to cover all possible changes and equivalent arrangements.

Claims (10)

1. A grayscale conversion method comprising the following steps: (a) receiving an input image, the input image has an N-bit first gray scale, and N is a natural number; (b) selectively calculating a first color gradation based on the M high bits and T low bits of the first gray scale, and calculating a second color gradation and a third color gradation based on the M high bits, M and T are a natural number, and M plus T equals N; and (c) converting the first color gradation, the second color gradation, and the third color gradation into an N-bit second grayscale by using a grayscale conversion formula, The gray scale conversion formula is Y ₂ =(a*C ₁ +b*C ₂ +c*C ₃ )*2 ^NM , and _Y2 is the second gray scale, a is equal to

b plus c equals Wherein step (b) further comprises the following steps: (b1) judging whether the first grayscale is smaller than a threshold, if yes, proceed to step (b2), if not, proceed to step (b3); (b2) Calculating a third gray scale Y ₃ , the first color scale C ₁ , the second color scale C ₂ and the third color scale C ₃ according to the following formula 1, Formula one: $\left\{\begin{array}{c}{Y}_3=Y_1*\frac{(2^{N-1}-1)-x_1}{2^{N-1}}\\ C_1=Y_3\left[m\right]+Y_3\left[T\right]\\ C_2=Y_3\left[m\right]\\ C_3=Y_3\left[m\right]\end{array}\right.;$ (b3) Calculate a fourth grayscale Y ₄ , the first color gradient C ₁ , the second color gradient C ₂ and the third color gradient C ₃ according to the following formula 2, Formula two: $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span>\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span>\end{array}\right.$ Wherein, Y ₁ is the first gray scale, X ₁ is a first predetermined value, X ₂ is a second predetermined value, X ₁ plus X ₂ is equal to 2 ^(NM) -1, Y ₃ [M] represents the The M high bits of the third gray scale, Y ₃ [T] means the T low bits of the third gray scale, Y ₄ [M] means the M high bits of the fourth gray scale, Y ₄ [T] means T low bits of the fourth gray scale. 2. The method of claim 1, wherein the first color gradation is a blue gradation, the second color gradation is a green gradation, and the third color gradation is a red gradation. 3. The method of claim 1, wherein the first color gradation is a red gradation, the second color gradation is a blue gradation, and the third color gradation is a green gradation. 4. The method of claim 1, wherein the first color gradation is a green gradation, the second color gradation is a red gradation, and the third color gradation is a blue gradation. 5. The method of claim 1, wherein the threshold is set to ^2N-1 . 6. A grayscale conversion device, comprising: A receiving module, used to receive an input image, the input image has an N-bit first grayscale, where N is a natural number; An encoding module, used to selectively calculate a first color gradation according to the M high bits and T low bits of the first gray scale, and calculate a second color gradation and a third color according to the M high bits Degree, M and T are a natural number, and M plus T is equal to N, wherein the coding module further includes: A judging unit, used for judging whether the first gray scale is smaller than a threshold, if so, calculate a third gray scale Y ₃ , the first color scale C ₁ , and the second color scale according to the following formula 1 C ₂ and the third color gradation C ₃ , if not, then calculate a fourth gray scale Y ₄ , the first color gradation C ₁ , the second color gradation C 2 and the first color gradation C ₂ according to the following formula 2 Three-color gradation C ₃ , Formula one: $\left\{\begin{array}{c}{Y}_3=Y_1*\frac{(2^{N-1}-1)-x_1}{2^{N-1}}\\ C_1=Y_3\left[m\right]+Y_3\left[T\right]\\ C_2=Y_3\left[m\right]\\ C_3=Y_3\left[m\right]\end{array}\right.,$ Formula two: $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span>\\ {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span>\end{array}\right.<span\; class="notranslate">\; ;</span>$ Wherein, Y ₁ is the first gray scale, X ₁ is a first predetermined value, X ₂ is a second predetermined value, X ₁ plus X ₂ is equal to 2 ^(NM) -1, Y ₃ [M] represents the The M high bits of the third gray scale, Y ₃ [T] means the T low bits of the third gray scale, Y ₄ [M] means the M high bits of the fourth gray scale, Y ₄ [T] means T lower bits of the fourth gray scale; and A decoding module is used to convert the first color gradation, the second color gradation and the third color gradation into an N-bit second grayscale through a grayscale conversion formula, wherein the grayscale The conversion formula is Y ₂ =(a*C ₁ +b*C ₂ +c*C ₃ )*2 ^NM , and _Y2 is the second gray scale, a is equal to

b plus c equals

7. The device of claim 6, wherein the first color gradation is a blue gradation, the second color gradation is a green gradation, and the third color gradation is a red gradation. 8. The device of claim 6, wherein the first color gradation is a red gradation, the second color gradation is a blue gradation, and the third color gradation is a green gradation. 9. The device of claim 6, wherein the first color gradation is a green gradation, the second color gradation is a red gradation, and the third color gradation is a blue gradation. 10. The apparatus of claim 6, wherein the threshold is set to ^2N-1 .

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