TW201443865A - Image color adjusting method and electronic apparatus thereof - Google Patents

Abstract

An image color adjusting method and electronic apparatus thereof are provided. A plurality of first pixel data of an image within a first color space is obtained, and a color space transform is performed to the first pixel data, so as to obtain a plurality of second pixel data of the image within a CIELAB color space. Each of the second pixel data comprises a luminance component L*, a first color component a* and a second color component b*. A plurality of third pixel data is obtained by adjusting the first color components and the second color components of the second pixel data, and the color space transform is then performed to the third pixel data, so as to obtain a plurality of fourth pixel data within the first color space and corresponding to the third pixel data.

Description

Image color adjustment method and electronic device thereof

The present invention relates to an image processing method and an electronic device thereof, and more particularly to an image color adjustment method capable of enhancing color saturation and an electronic device thereof.

With the advancement of display technology, image display functions have been widely used in various types of electronic devices as a means of transmission and method of information. Furthermore, the user can select to play related images or pictures on a suitable electronic device according to the location, occasion, time and other factors. For example, a video is played on a handheld device such as a tablet computer or a large home appliance such as a television. However, in order to enable users to obtain high-quality images and brighter colors, various image processing methods have been proposed and applied to different devices.

In the pursuit of high-quality images, increasing the color saturation of the image allows viewers to see more vivid colors and clearer images. For example, when multiple pixel data of an image is defined in the RGB color space, the color saturation of the image can be adjusted by adjusting the red component, the green component, or the blue component of the pixel data. And degree. However, if the single color component of the image is directly adjusted or enhanced in the RGB color space, the image is often distorted, and the image may be too bright after adjustment to cause a false contour phenomenon.

The present invention provides an image color adjustment method for color adjustment of an image in a specific color space to enhance the color saturation of the image.

The present invention provides an electronic device, after receiving pixel data of an image, performing color space conversion on the pixel data of the image by using an image processing unit, and performing color adjustment on the pixel data in a specific color space to provide and display An image with better quality.

The image color adjustment method in the embodiment of the present invention is used on an electronic device having image processing capability, and is suitable for color adjustment of an image. The method includes: acquiring a plurality of sets of first pixel data in an image in a first color space, and performing color space conversion on the first pixel data to obtain a plurality of sets of second pixel data in the CIELAB color space of the image, Each of the second pixel data includes a luminance component (L*), a first color component (a*), and a second color component (b*). Adjusting a first color component (a*) and a second color component (b*) in the second pixel data to obtain a plurality of sets of third pixel data, and performing color space conversion on the third pixel data to obtain In the first color space, a plurality of sets of fourth pixel data corresponding to the third pixel data.

The electronic device in the embodiment of the present invention has an image processing function and is suitable for color adjustment of an image. The electronic device includes an image receiving unit and an image processing unit And display the screen. The image receiving unit receives the image and obtains a plurality of sets of first pixel data in the first color space. The image processing unit is coupled to the image receiving unit to perform color space conversion on the first pixel data to obtain a plurality of sets of second pixel data in the CIELAB color space, wherein each set of second pixel data includes a brightness component ( L*), first color component (a*) and second color component (b*). The image processing unit further adjusts the first color component (a*) and the second color component (b*) in the second pixel data by using the color adjustment model to obtain a plurality of sets of third pixel data, and the third pixel data Color space conversion is performed to obtain a plurality of sets of fourth pixel data corresponding to the third pixel data in the first color space. The display screen is coupled to the image processing unit for receiving and displaying the image composed of the fourth pixel data.

Based on the above, the image color adjustment method and the electronic device thereof in the embodiment of the present invention convert the pixel data of the image from the other color space into the CIELAB color space and perform color adjustment. Through the color adjustment model proposed in the embodiment of the present invention, the image color adjustment method further adjusts the first color component and the second color component of the pixel data in the CIELAB color space, thereby improving the color saturation of the image, and adjusting the image. The pixel data is redirected to the original color space for easy output and display. Thereby, the color saturation of the image can be increased to increase the vividness of the image while avoiding defects such as image distortion.

In order to make the above features and advantages of the present invention more comprehensible, the following embodiments are described in detail with reference to the accompanying drawings.

100‧‧‧Electronic devices

120‧‧‧Image receiving unit

140‧‧‧Image Processing Unit

142‧‧‧ Skin Detection Unit

160‧‧‧display screen

S220, S240, S242, S244, S260, S262, S264, S280‧‧‧ steps of image color adjustment method

FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention.

2 is a flow chart of an image color adjustment method according to an embodiment of the present invention.

FIG. 3 is a flowchart of an image color adjustment method according to another embodiment of the present disclosure.

4 is a schematic diagram of a color adjustment model according to an embodiment of the present disclosure.

Reference will now be made in detail to the embodiments of the present invention, In addition, wherever possible, the same elements in the figures and the

The image color adjustment method provided by the embodiment of the present invention is used on an electronic device having an image processing function, and is suitable for color adjustment of an image. Generally, the image is composed of a plurality of pixels, so the image data includes a plurality of sets of pixel data defined in a color space, and the image color method provided by the embodiment of the present invention will be the plurality of groups. The pixel data is color space transformed (Color Space Transform) to use the color adjustment model to color the image in the CIELAB color space to avoid image distortion.

FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention. Referring to FIG. 1 , the electronic device 100 includes an image receiving unit 120 , an image processing unit (IPU) 140 , and a display screen 160 . Suitable for color adjustment of images like processing functions. In more detail, the image receiving unit 120 receives an image from the outside and transmits the plurality of sets of pixel data of the image to the image processing unit 140. The image processing unit 140 is coupled to the image receiving unit 120, and receives and performs image processing on the image. The processed image is output to the display screen 160, and the image processed image is displayed by the display screen 160. The display screen 160 can be a liquid crystal display (LCD Display) or a light-emitting diode display (LED Display), but the case is not limited thereto.

2 is a flow chart of an image color adjustment method according to an embodiment of the present invention. Referring to FIG. 1 and FIG. 2, the image color adjustment method includes the following steps. In step S220, the image receiving unit 120 acquires a plurality of sets of first pixel data in the first color space. In this embodiment, the first color space is a red-green-blue (RGB) color space, and each set of first pixel data includes a red component, a green component, and a blue component. (Blue Component). However, in other embodiments of the present disclosure, the first color space is not limited to the red-green-blue color space, but may be other types of color spaces, such as a printed quad color (CMYK) color space.

Next, in step S240, the image processing unit 140 receives the plurality of sets of first pixel data, and performs color space conversion on the first pixel data to obtain multiple sets of second pixel data in the CIELAB color space. . Under the definition of CIELAB color space, the second pixel data includes a Luminance Component (L*), a First Color Component (a*), and a Second Color Component (b*). In more detail, the luminance component (L*) Representing the brightness of a single pixel, the first color component (a*) represents the degree of deflection of a single pixel color between red and green (opposite colors), while the second color component (b*) represents a single pixel color in yellow and The degree of bias between blue (opposite colors). Due to the visual uniformity in the CIELAB color space, color adjustments in the CIELAB color space can be more accurately mapped to visually perceived color variations.

In this embodiment, the first color space is a red-green-blue color space, however, it should be noted that the pixel data in the red-green-blue color space and the CIELAB color space cannot be directly converted. Therefore, in this embodiment, it is further required to convert the first pixel data of the image in the red-green-blue color space into the CIELAB color space by using a transition color space, such as the CIEXYZ color space. Second pixel data. The specific method is to perform color space conversion on the first pixel data to obtain transition pixel data corresponding to the first pixel data in the transition color space. Then, the transition pixel data is subjected to color space conversion to obtain the second pixel data corresponding to the transition pixel data in the CIELAB color space.

In step S260, the image processing unit 140 adjusts the first color component (a*) and the second color component (b*) in each second pixel data by using the color adjustment model to obtain a plurality of sets of third pixel data. The color adjustment model proposed in the embodiment of the present invention is: Where x is the input first color component (a*) or second color component (b*), and f(x) is the first color component (a*) or the second color component (b*) is mapped to 0~ 1 The color map value between the ranges, the parameters t and γ are control parameters, the parameters p and q are limit parameters, and g(x) is the color adjustment value after the color map value is adjusted by the color adjustment model. In an embodiment of the present invention, the limit parameters p and q are preferably an integer.

4 is a schematic diagram of a color adjustment model according to an embodiment of the present disclosure. Referring to FIG. 4 and the foregoing color adjustment model (Equation 1), the curve in FIG. 4 is the correspondence between the color map value f(x) and the color adjustment value g(x) in the color adjustment model (Equation 1), in other words. That is, the correspondence between the input first color component (a*) or the second color component (b*) and the output first color component (a*) or second color component (b*). The first color component (a*) or the second color input when the first color component (a*) and the second color component (b*) in the second pixel data are adjusted by the color adjustment model (Equation 1) The component (b*) is first mapped to a range of 0~1 to obtain the color map value f(x), and the color adjustment value g(x) is remapped back to the first color component (a*) after color adjustment. Or a range of values of the second color component (b*) to obtain a plurality of sets of third pixel data. The third pixel data also includes a luminance component (L*), a first color component (a*), and a second color component (b*).

In the present embodiment, by adjusting the control parameters t and γ and the limit parameters p and q, the magnitude of change of the first color component (a*) and the second color component (b*) can be adjusted correspondingly. The control parameters t and γ may determine the degree to which the first color component (a*) and the second color component (b*) are adjusted, while the limiting parameters p and q are used to limit the first color component (a*) and the second. The color component (b*) prevents the first color component (a*) and the second color component (b*) from being excessively amplified to cause the image color to be oversaturated. In the embodiment of the present invention, preferably, the control parameters t and γ are in accordance with 0. γ 4 and 0.99 t 1.91, and the limit parameters p and q match 0<p 2 and 0<q 1.

As mentioned above, in the CIELAB color space, the first color component (a*) represents the degree of deflection of a single pixel color between red and green (opposite colors), while the second color component (b*) represents a single pixel color. The degree of bias between yellow and blue (opposite colors). Therefore, in the correspondence relationship of FIG. 4, if the input color map value f(x) is biased toward 1, it indicates that the first color component (a*) is biased toward red or represents the second color component (b*). The more yellowed. On the other hand, if the input color map value f(x) is biased toward 0, it means that the first color component (a*) is biased toward green, or the second color component (b*) is biased toward blue. As can be seen from Figure 4, the color adjustment model has the ability to adjust the degree to which the color components are biased between opposite colors. For example, when the input color map value f(x) is 0.8, the color adjustment value outputted in FIG. 4 is 0.9 after being adjusted by the color adjustment model (Equation 1). If x is the first color component (a*), it means that the more it is adjusted by the color model, the more it is red, and if x is the second color component (b*), it means that it is more yellow.

In the CIELAB color space, the chromaticity C* is defined as:

The color saturation Sab is defined as follows: In general, the range of values of the first color component (a*) and the second color component (b*) in the CIELAB color space is in accordance with -R a* R and -R b * R , where R is any integer. As described above, since the color adjustment model (Equation 1) has the ability to adjust the degree of deviation of the color component between opposite colors, the image processing unit 140 can adjust the control parameters t and γ for the image (or its pixels). The chromaticity C* is relatively increased, and the color saturation S _{ab is} further increased without affecting the brightness L* of the image.

Referring back to FIG. 1 and FIG. 2, after acquiring a plurality of sets of third pixel data, the image processing unit 140 performs color space conversion on the plurality of sets of third pixel data in step S280 to obtain the corresponding color space. Multiple sets of fourth pixel data for the third pixel data. In this embodiment, the first color space is a red-green-blue color space, so the fourth pixel data also includes a red component, a green component, and a blue component.

FIG. 3 is a flowchart of an image color adjustment method according to another embodiment of the present disclosure. In this embodiment, the method of adjusting the first color component (a*) and the second color component (b*) in each set of second pixel data by using the color adjustment model (Equation 1) can be further subdivided into Perform color enhancement processing on the second pixel data and color adjustment processing on part of the second pixel data. Referring to FIG. 3, after performing color space conversion on the first pixel data in step S240 to obtain a plurality of sets of second pixel data in the CIELAB color space, the image processing unit 140 uses the color adjustment model in step S262. Equation 1) enhances the first color component (a*) and the second color component (b*) in the second pixel data. By adjusting the control parameters t and γ and limiting the parameters p and q, the color adjustment model (Equation 1) can adjust the first color component (a*) and the second color component (b*) as in the corresponding relationship in FIG. To enhance the first color component (a*) and the second color component (b*), thereby achieving the purpose of improving the color saturation of the second pixel data.

In addition to the first pixel data and the second pixel data in the second pixel data In addition to the color enhancement process, the present embodiment further includes color adjustment for the skin color region in the image. If the image has a skin color region (which usually represents the presence of a person in the image), the image processing unit 140 further adjusts the second pixel data corresponding to the skin color region after the color enhancement process in step S262. The first color component (a*) and the second color component (b*) are such that the display screen 160 better expresses the skin color region of the skin color in the image.

Referring to FIG. 3, after acquiring a plurality of sets of first pixel data in the first color space in step S220, the image processing unit 140 further performs color space conversion on the plurality of sets of first pixel data in step S242. To obtain a plurality of sets of fifth pixel data in the second color space. For example, the second color space may be an HSV color space, and each fifth pixel material includes a hue component (H), a saturation component (S), and a luminance component (V). Next, in step S244, skin color detection is performed on the plurality of groups of fifth pixel data to determine whether the skin color region of the skin color is present in the image. Referring to FIG. 1, the image processing unit 140 further includes a skin color detecting unit 142 to detect a skin color region in the image. Taking the HSV color space as an example, the skin color detecting unit 142 determines the image by respectively setting the hue component (H), the saturation component (S), and the luminance component (V) in an appropriate range and comparing the fifth pixel data. Whether there is a skin color area in the middle.

If there is no skin color region in the image, then in step S262, the plurality of sets of third pixel data obtained by adjusting the color adjustment model (Equation 1) are obtained, and The image processing unit 140 obtains the fourth pixel data corresponding to the third pixel material in the first color space in step S280. On the other hand, if there is a skin color region in the image, the image processing unit 140 further adjusts the first color component (a*) and the second color of the second pixel data of the portion by using the color adjustment mode (Equation 1) in step S264. The component (b*), while the second pixel data of the aforementioned portion corresponds to the skin color region in the image.

In more detail, the color adjustment model (Equation 1) can also be used to adjust the skin color region by adjusting the control parameters t and γ and limiting the parameters p and q. It is to be noted that in steps S262 and S264, the control parameters t and γ of the color adjustment model (Equation 1) and the limit parameters p and q do not coincide with each other in setting. The color adjustment model used in step S264 is compared to the color adjustment model (Equation 1) for enhancing the first color component (a*) and the second color component (b*) of the second pixel material in step S262. (Equation 1) has lower control parameters t and γ values to appropriately reduce the color saturation of the skin color region. Finally, after the image processing unit 140 obtains the third pixel data adjusted in step S262 and step S264, the fourth pixel data corresponding to the third pixel data in the first color space is obtained in step S280.

In summary, the image color adjustment method and the electronic device provided in the embodiment of the present invention can convert pixel data defined in other color spaces in the image to the CIELAB color space, and by using the proposed color adjustment model, Adjust the color saturation of the image without distorting the image or making it too bright. In addition, the image color adjustment method can also detect whether there is a skin color region of the skin color in the image, and adjust the skin color region in the image with the same color adjustment model, so that the display screen can better display the skin color in the image. region.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present case. Any person having ordinary knowledge in the technical field can protect the case without making any changes or refinements without departing from the spirit and scope of the present case. The scope is subject to the definition of the scope of the patent application.

S220, S240, S260, S280‧‧‧ steps of image color adjustment method

Claims (14)

An image color adjustment method for an electronic device having an image processing function, the image color adjustment method comprising: acquiring a plurality of sets of first pixel data in an image in a first color space; and the first pixels Data is converted into a color space to obtain a plurality of sets of second pixel data in the CIELAB color space, wherein each of the second pixel data includes a luminance component (L*) and a first color component (a*) And the second color component (b*); adjusting the first color component (a*) and the second color component (b*) in the second pixel data to obtain a plurality of sets of third pixel data; And performing color space conversion on the third pixel data to obtain a plurality of sets of fourth pixel data corresponding to the third pixel data in the first color space. The image color adjustment method according to claim 1, wherein the first color space is a red-green-blue (RGB) color space, and each of the first pixel materials and each of the fourth pixels The pixel data includes a red component (R), a green component (G), and a blue component (B), respectively. The image color adjustment method according to claim 1, wherein the image color adjustment method further adjusts the second pixel data by using a color adjustment model, wherein the color adjustment model is: Where x is the input first color component (a*) or the second color component (b*), and f(x) is the first color component (a*) or the second color component (b*) Map to the color map value between 0~1 range, parameters t and γ are control parameters, parameters p and q are limit parameters, and g(x) is the color map value f(x) adjusted by the color adjustment model Color adjustment value. The image color adjustment method according to claim 3, wherein the control parameters t and γ are in accordance with 0. γ 4 and 0.99 t 1.91, and the limit parameters p and q match 0<p 2 and 0<q 1. The image color adjustment method of claim 1, wherein the step of adjusting the first color component (a*) and the second color component (b*) in the second pixel data comprises: enhancing The first color component (a*) and the second color component (b*) in the second pixel data to enhance the color saturation of the second pixel data. The image color adjustment method of claim 5, further comprising: performing color space conversion on the first pixel data to obtain a plurality of groups of fifth pixel data in the second color space; And performing skin color detection on the fifth pixel data to determine whether the image has a skin color region of the skin color; wherein if the skin color region is included in the image, the second color is enhanced After the color saturation of the pixel data, the first color component (a*) and the second color component (b*) of the second pixel data of the portion are adjusted, wherein the second pixels of the foregoing portion The data corresponds to the skin color region in the image. The image color adjustment method described in claim 6 of the patent application, wherein the method The second color space is an HSV color space, and each of the fifth pixel data includes a hue component (H), a saturation component (S), and a luminance component (V). An electronic device includes an image processing function, the electronic device includes: an image receiving unit that receives an image and obtains a plurality of sets of first pixel data in the first color space; and an image processing unit coupled to the image The receiving unit performs color space conversion on the first pixel data to obtain a plurality of sets of second pixel data in the CIELAB color space, wherein each of the second pixel data includes a luminance component (L*) a first color component (a*) and a second color component (b*), the image processing unit adjusting the first color component (a*) in the second pixel data with a color adjustment model a second color component (b*) to obtain a plurality of sets of third pixel data, and performing color space conversion on the third pixel data to obtain the first color space corresponding to the third pixels a plurality of sets of fourth pixel data of the data; and a display screen coupled to the image processing unit for receiving and displaying the image composed of the fourth pixel data. The electronic device of claim 8, wherein the first color space is a red-green-blue (RGB) color space, and each of the first pixel data and each of the fourth pixels The data includes a red component (R), a green component (G), and a blue component (B), respectively. The electronic device of claim 8, wherein the color adjustment model is: Where x is the input first color component (a*) or the second color component (b*), and f(x) is the first color component (a*) or the second color component (b*) Map to the color map value between 0~1 range, parameters t and γ are control parameters, parameters p and q are limit parameters, and g(x) is the color map value f(x) adjusted by the color adjustment model Color adjustment value. The electronic device of claim 10, wherein the control parameters t and γ are in accordance with 0. γ 4 and 0.99 t 1.91, and the limit parameters p and q match 0<p 2 and 0<q 1. The electronic device of claim 8, wherein the image processing device enhances the first color component (a*) and the second color component in the second pixel data by the color adjustment model ( b*) to increase the color saturation of the second pixel data. The electronic device of claim 12, wherein the image processing unit further comprises a skin color detecting unit, wherein the image processing unit performs color space conversion on the first pixel data to obtain the image in the second The plurality of sets of fifth pixel data in the color space, and the skin color detecting unit performs skin color detection on the fifth pixel data to determine whether the image has a skin color region of the skin color. The electronic device of claim 13, wherein the second color space is an HSV color space, and each of the fifth pixel data comprises a hue component (H), a saturation component (S), and A luminance component (V).