CN1832584A - Dynamic image contrast adjustment device - Google Patents

Abstract

The invention provides a dynamic image adjusting device, which is used for dynamically adjusting the contrast of a first image signal, wherein the first image signal comprises a plurality of pixels, and the adjusting device comprises a first conversion module, an operation module and a second conversion module. The first conversion module receives a first image signal for generating a plurality of adjustment signals, wherein each pixel corresponds to an adjustment signal. The operation module is connected to the first conversion module, and receives a first group of adjustment signals in the plurality of adjustment signals to generate a first gain curve. The second conversion module is connected to the operation module and the first conversion module, and generates a second image signal according to the first gain curve and the plurality of adjustment signals.

Description

Dynamic image contrast adjustment device

technical field

The present invention relates to a dynamic image adjustment device, in particular to an image adjustment device for dynamically adjusting the contrast of an image signal.

Background technique

In general, the contrast of a natural image refers to the brightness ratio between bright and dark regions in the image. Therefore, the enhancement of image contrast may cause slight distortion of the image, but for most people, appropriate contrast enhancement will be more comfortable for human vision, so how to enhance the contrast of the image has become an important topic.

In the current display technology, the enhancement of the image contrast can be adjusted by using the Gamma (gamma) parameter of the display, and the image contrast can be adjusted by changing the relationship between the gray signal and the brightness. The on screen display control function (on screen display, OSD) adjusts the contrast by itself, or provides Gamma parameters for users to choose to improve the contrast, but a single contrast setting cannot be applied to all images. For example, for an image with high overall brightness, the user may choose a larger Gamma parameter or change the contrast setting to enhance the contrast of the image, but when such a setting is used for an image with low brightness, it will Making the low-light parts of the image too dark and losing detail degrades the image quality. Therefore, better contrast adjustment must be dynamically adjusted according to different images, that is, different adjustments must be made for different brightness of each image.

The concept of contrast enhancement is to make the bright part of the image brighter and the dark part darker. We only want to adjust the brightness of the image, but do not want to change the color. Therefore, in the brightness and color separation (Y/C) color space, ideally in the traditional RGB color space. In the current display technology, the Y component of the YPbPr signal or YCbCr signal can also be changed through a video decoder or a scaler chip, that is, the image contrast is adjusted by the brightness gain. For an image or picture, what the human eye can perceive is its hue (Hue), brightness (Brightness) and color saturation (Saturation). Since the RGB signal includes brightness and color at the same time, when you only want to process the color of the display , directly adjusting the RGB grayscale signal cannot achieve the purpose, so the brightness and color in the color signal must be separated before the brightness or color can be adjusted separately. High-quality image signals also separate brightness and color (YPbPr, YCbCr) during transmission, so when you want to adjust the contrast of the display, you can also adjust the Y component in the image signal. In the current display technology, although there are methods to adjust image contrast, they all use YCbCr signal or YPbPr signal to adjust image contrast. However, in the characteristics of YCbCr or YPbPr signal, the separation effect of brightness and color is worse than that of CIELab signal. Therefore, The effect of the adjustment is also poorer than that of image contrast adjustment using the Lab signal.

Therefore, the main purpose of the present invention is to provide a dynamic image adjustment device to overcome the above problems.

Contents of the invention

The purpose of the present invention is to provide a dynamic image adjustment device, which can automatically and dynamically adjust the contrast of image signals according to different image signals.

According to the dynamic image adjustment device of the present invention, it is used to dynamically adjust the contrast of a first image signal, wherein the first image signal includes a plurality of pixels, and the adjustment device includes a first conversion module, an operation module and a second conversion module. The first conversion module receives the first image signal to generate a plurality of adjustment signals, wherein each pixel corresponds to an adjustment signal. The operation module is connected to the first conversion module, and the operation module receives a first set of adjustment signals among the plurality of adjustment signals to generate a first gain curve. The second conversion module is connected to the operation module and the first conversion module, and the second conversion module generates a second image signal according to the first gain curve and a plurality of adjustment signals.

The dynamic image adjustment device of the present invention uses the arithmetic module to calculate the image characteristics of each image, and the gain module adjusts the image signal correspondingly according to the image characteristics. By this method, the image signal can be automatically and dynamically adjusted according to different image signals. The contrast degree of the image screen can achieve a better effect.

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 system block diagram of the dynamic image adjustment device of the present invention.

FIG. 2 is a schematic diagram of the gain curve used by the adjusting device of the present invention.

FIG. 3 is a flow chart of the steps of the dynamic image adjustment method of the present invention.

FIG. 4 is a flow chart of steps for selecting a first gain curve in the dynamic image adjustment method of the present invention.

FIG. 5 is a flow chart of the steps of generating a second image signal by the image adjustment method of the present invention.

Description of main component symbols

20: Image adjustment device 21: First image signal

22: The first conversion module 23: Brightness signal

24: Operation module 25: First color signal

26: Second conversion module 27: Second color signal

28: storage device 30: brightness calculation module

31: Average brightness signal 32: Select module

34: Gain curve 35: The first gain curve

40: Regular module 41: Normalized adjustment signal

42: Gain module 43: Gain signal

44: Reverse conversion module 45: Second image signal

60, 62, 64: Gain curve

Detailed ways

Please refer to FIG. 1 . FIG. 1 is a system block diagram of a dynamic image adjusting device 20 of the present invention. The present invention is a dynamic image adjustment device 20 for dynamically adjusting the contrast of a first image signal 21, wherein the first image signal 21 includes a plurality of pixels, and the adjustment device 20 includes a first conversion module 22 and an operation module 24 And a second conversion module 26 .

The first conversion module 22 receives the first image signal 21 to generate a plurality of adjustment signals, wherein each pixel corresponds to an adjustment signal. Each of the adjustment signals includes a brightness signal 23 , a first color signal 25 and a second color signal 27 .

The computing module 24 is connected to the first converting module 22, and the computing module 24 receives a first set of adjusting signals among the plurality of adjusting signals to generate a first gain curve.

In one embodiment, the calculation module 24 includes a brightness calculation module 30 and a selection module 32 . The brightness calculation module 30 generates an average brightness signal 31 according to the brightness signal 23 of each adjustment signal in the first group of adjustment signals. The selection module 32 is connected to the brightness calculation module 30. The selection module 32 stores a plurality of gain curves 34 in advance. The selection module 32 selects the first gain curve 35 from the plurality of gain curves 34 according to the average brightness signal 31 .

The second conversion module 26 is connected to the computing module 24 and the first conversion module 22 , and the second conversion module 26 generates a second image signal 45 according to the first gain curve 35 and a plurality of adjustment signals.

The second conversion module 26 includes a normal module 40 , a gain module 42 and an inverse conversion module 44 . The normalization module 40 generates a plurality of normalized adjustment signals 41 according to the plurality of adjustment signals. The gain module 42 is connected to the normalization module 40 , and the gain module 42 generates a plurality of gain signals 43 according to the plurality of normalization adjustment signals 41 and the first gain curve 35 . The inverse conversion module 44 is connected to the gain module 42 , and the inverse conversion module 44 generates a second image signal 45 according to a plurality of gain signals 43 .

The gain module 42 includes a plurality of gain tables 50, wherein each gain table 50 in the plurality of gain tables 50 is corresponding to each gain curve 34 of the plurality of gain curves 34, and the gain module 42 is based on a corresponding one of the first gain curve 35. The first gain table is adjusted with a plurality of normalized signals 41 to generate a plurality of gain signals 43 .

In one embodiment, the adjustment device 20 further includes a storage device 28 connected to the computing module 24 for storing the average brightness signal 31 and the first group of brightness signals.

In addition, in another embodiment of the dynamic image adjustment device of the present invention, the average luminance signal can be selected from the storage device, and the average luminance signal can be used to calculate the average value. Because of the operation speed of the digital circuit, it is impossible to complete all the luminance signals before the screen is displayed. operation. In addition, when the general image screen is played, the content of the screen generally changes continuously. About 60 images are played per second, and the content of the previous and subsequent images will not change too much, so if you directly use the previous screen It is reasonable and feasible to adjust the image contrast with the calculated average luminance signal to adjust the next image, but when the image content changes greatly, it will easily cause the image to flicker. Therefore, in this embodiment, an operation of calculating the average value is added, for example, the average brightness signals of the previous 31 images are averaged, and then the 32nd image is adjusted using the calculated average value, so that the image size can be avoided. The flickering sensation caused by the amplitude change.

Please refer to FIG. 2 , which is a schematic diagram of the gain curve used by the adjusting device of the present invention. As shown in FIG. 2 , the horizontal axis represents the brightness of the input, and the vertical axis represents the brightness of the output after processing. Curve 60 represents a linear relationship with a slope of 1, that is, the brightness does not need any processing, or the gain value is 1. The curve 62 is similar to the Gamma curve, and is used for images with high overall brightness. Curve 64 is an inverse curve, which makes the bright part of the image brighter and the dark part darker, and the upper and lower amplitudes can be adjusted to make it suitable for images with intermediate or low brightness. The dynamic contrast adjustment mentioned in the present invention is the brightness feature of the image as a whole, dynamically select the gain curve of the input and output of the brightness component as shown in Figure 2, and then use the gain table corresponding to the gain curve to make the Image contrast enhancement.

Please refer to FIG. 3 . FIG. 3 is a flow chart of the steps of the dynamic image adjustment method of the present invention. The present invention provides a dynamic image adjustment method for dynamically adjusting the contrast of a first image signal, wherein the first image signal includes a plurality of pixels, and the adjustment method includes the following steps:

S70: Receive the first image signal to generate a plurality of adjustment signals, wherein each pixel corresponds to an adjustment signal; wherein each adjustment signal in the plurality of adjustment signals includes a brightness signal, a first color signal and a second color signal color signal.

S72: Receive a first group of adjustment signals among the plurality of adjustment signals to generate a first gain curve; and

S74: Generate a second image signal according to the first gain curve and a plurality of adjustment signals.

Please refer to FIG. 4 . FIG. 4 is a flow chart of steps for selecting the first gain curve in the dynamic image adjustment method of the present invention. Wherein the method pre-stores a plurality of gain curves, as shown in Figure 4, step S72 includes:

S80: Generate an average brightness signal according to the brightness signal of each adjustment signal in the first group of adjustment signals; and

S82: Select a first gain curve from the plurality of gain curves according to the average brightness signal.

As shown in Figure 3, the method also includes:

S76: Store the average brightness signal and the first group of brightness signals.

Please refer to FIG. 5 . FIG. 5 is a flow chart of the steps of generating the second image signal by the image adjustment method of the present invention. As shown in Figure 5, step S74 additionally includes:

S90: Generate a plurality of normalized adjustment signals according to the plurality of adjustment signals;

S92: Generate a plurality of gain signals according to a plurality of normalized adjustment signals and the first gain curve; wherein each gain curve of the plurality of gain curves corresponds to each gain table in the plurality of gain tables, and this step is based on the first gain curve A first gain table and a plurality of normalized adjustment signals are corresponding to generate a plurality of gain signals.

S94: Generate a second image signal according to a plurality of gain signals.

所提出的CIELab色彩空间，或称Lab色彩空间。采用Lab的原因有二，一是Lab色彩空间为感觉均等(perceptional uniform)的色彩空间，另一原因是Lab色彩空间是亮度与颜色分离的，且分离程度较其他色彩空间明显。因此通过本发明的动态图像调整装置将可提高画面的品质，使图像有更丰富的视觉效果，让显示器所呈现的画面表现出更佳的效果。The present invention provides a dynamic image adjustment device, which uses a brightness calculation device to generate the average brightness of the first group of adjustment signals, and a selection module selects a gain curve according to the average brightness, and then performs a normalized operation on the adjustment signals to generate a normalized adjustment signal, and then Calculate and adjust the normalized adjustment signal and the gain value in the gain table corresponding to the gain curve to obtain the adjusted gain signal, and then use the reverse module to convert the gain signal to generate a second image signal that can be displayed on the display to complete the image contrast adjustment operation. Therefore, the dynamic image adjustment device of the present invention can automatically and dynamically adjust the contrast of each image with different image contents, and the color space used by the present invention is CIE (Commission Internationale de L'

The proposed CIELab color space, or Lab color space. There are two reasons for using Lab. One is that the Lab color space is a perceptual uniform color space. The other reason is that the Lab color space separates brightness and color, and the degree of separation is more obvious than other color spaces. Therefore, the dynamic image adjustment device of the present invention can improve the quality of the picture, make the picture have richer visual effects, and make the picture presented by the display show a better effect.

Through the detailed description of the preferred specific embodiments above, it is hoped that the features and spirit of the present invention can be described more clearly, rather than the scope of the present invention is limited by the preferred specific embodiments disclosed above. On the contrary, the intention is to cover various modifications and equivalent arrangements within the scope of the appended claims.

Claims (12)

1. dynamic image adjusting device, in order to the contrast of dynamic adjustment one first picture signal, wherein this first picture signal comprises a plurality of pixels, and this adjusting device comprises:

One first modular converter receives this first picture signal in order to produce a plurality of adjustment signals, and wherein each pixel corresponds respectively to one and adjusts signal;

One computing module is connected to this first modular converter, and this computing module receives one first group of adjustment signal in these a plurality of adjustment signals, to produce one first gain curve; And

One second modular converter, this second modular converter are connected to this computing module and this first modular converter, this second modular converter according to this first gain curve and these a plurality of adjustment signals to produce one second picture signal.

2. adjusting device as claimed in claim 1, wherein each adjustment signal comprises a luminance signal, one first color signal and one second color signal in these a plurality of adjustment signals.

3. adjusting device as claimed in claim 2, this computing module comprises:

One brightness calculation module is according to this first group this luminance signal of adjusting each adjustment signal in the signal, to produce an average luminance signal; And

One selects module, is connected to this brightness calculation module, and this selections module system stores many gain curves in advance, this select module according to this average luminance signal with this first gain curve of selection in this many gain curves certainly.

4. adjusting device as claimed in claim 3, this adjusting device also comprises a storage device, in order to store this average luminance signal and this first group of luminance signal.

5. adjusting device as claimed in claim 1, wherein this second modular converter comprises:

One regular module, this regular module is adjusted signal according to these a plurality of adjustment signals to produce a plurality of normalizations;

One gain module is connected to this regular module, and these a plurality of normalization adjustment signals of this gain module foundation and this first gain curve are to produce a plurality of gain signals; And

One reverse conversion module is connected to this gain module, and these these a plurality of gain signals of reverse conversion module foundation are to produce this second picture signal.

6. the described adjusting device of claim 5, wherein this gain module comprises a plurality of gain table, wherein each gain table is each bar gain curve of corresponding these many gain curves in these a plurality of gain table, this gain module is adjusted signal according to a plurality of normalizations of pairing one first gain table of this first gain curve and this, to produce these a plurality of gain signals.

7. dynamic image method of adjustment, in order to the contrast of dynamic adjustment one first picture signal, wherein this first picture signal comprises a plurality of pixels, and this method of adjustment comprises the following step:

(a) receive this first picture signal in order to produce a plurality of adjustment signals, wherein each pixel corresponds respectively to one and adjusts signal;

(b) receive one first group of adjustment signal in these a plurality of adjustment signals, to produce one first gain curve: and

(c) according to this first gain curve and these a plurality of adjustment signals to produce one second picture signal.

8. method as claimed in claim 7, wherein each adjustment signal comprises a luminance signal, one first color signal and one second color signal in these a plurality of adjustment signals.

9. method as claimed in claim 8, wherein this method system stores many gain curves in advance, and step (b) comprises:

(b1) according to this first group this luminance signal of adjusting each adjustment signal in the signal, to produce an average luminance signal; And

(b2) according to this average luminance signal to select this first gain curve in this many gain curves certainly.

10. method as claimed in claim 9, wherein this method also comprises:

(d) store this average luminance signal and this first group of luminance signal.

11. method as claimed in claim 7, wherein this step (c) comprises in addition:

(c1) adjust signal according to these a plurality of adjustment signals to produce a plurality of normalizations;

(c2) these a plurality of normalization adjustment signals of foundation and this first gain curve are to produce a plurality of gain signals; And

(c3) these a plurality of gain signals of foundation are to produce this second picture signal.

12 methods as claimed in claim 11, wherein each bar gain curve of these many gain curves is each gain table in corresponding a plurality of gain table, step (c2) is to adjust signal according to a plurality of normalizations of pairing one first gain table of this first gain curve and this, to produce these a plurality of gain signals.

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