JP3043206B2 - Video signal processing apparatus and video signal processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus and a video signal processing method, and more particularly, to a video signal used for an image pickup section such as a video camera, and more particularly to a color signal such as a color difference signal and a color signal. The present invention relates to an improvement in a signal processing apparatus and a signal processing method.

[0002]

2. Description of the Related Art In an image pickup section of a general CCD camera, an appropriate color display of an image is realized by performing various kinds of signal processing on an output signal from the CCD. One of the signal processing is white balance adjustment.
White balance is when a white subject is imaged.
This is to make the level of the color components (R, G, B) of the video signal obtained from the CCD equipped with the color filter uniform, and by properly taking this state, a white subject is represented as white. That is, it is possible to obtain an image of a normal color in which the entire screen is not reddish or bluish. Therefore, the output signals (R,
G, B) requires a process of applying an appropriate gain. This gain is called a white balance gain.

As one method of adjusting the white balance gain, a color difference signal (R) obtained by subtracting a luminance signal (Y) from signals of respective primary colors of R (red), G (green), and B (blue) is used. −Y, GY, and BY) are integrated for each screen, and a method of setting a white balance gain such that the integrated values converge to predetermined values (generally, 0) is proposed. Have been.

That is, if a color difference signal (R
-Y, GY, BY) exceeds a predetermined value, the ratio of the color to the screen is large,
The screen is dominated by that color. For example, if the integrated value of the color difference signal (R-Y) for red exceeds a predetermined value, the entire screen becomes reddish. Therefore, when the white balance is properly maintained, one of the color difference signals (RY, GY, BY) of all the primary colors is obtained.
Since the integral value of the screen should be 0, each color difference signal (RY, GY, BY) is integrated for one screen, and each color difference signal is processed so that the integral value becomes 0. What is necessary is just to set the applied white balance gain.

Specifically, taking blue as an example, an integral value of a color difference signal (BY) with respect to blue is calculated for each screen, and B
The white balance gain (Bg) applied to [blue] is set to lower Bg when the integral value of (BY)> 0, and to increase Bg when the integral value of (BY) <0. . Such setting is G [green], R
By performing the same for [red], each color difference signal (R-
The integrated value for one screen of (Y, GY, BY) converges to zero. Therefore, by adjusting the white balance gain in this way, the white balance is brought into an appropriate state.

FIG. 5 shows an example of an apparatus for realizing the above method. As shown in FIG. 5, the video signal processing device according to the conventional example includes an integration circuit (1), a white balance gain generation unit (2), a balance adjustment circuit (3), and a color difference matrix circuit (4). The integrating circuit (1), the white balance gain generating section (2) and the balance adjusting circuit (3) are provided in each of the R [red] system and the G [green] system. ] It has the same configuration as the system circuit, and the description is omitted.

According to this device, first, the color difference signals (BY) for blue are sequentially input from the color difference matrix circuit (4) to the integration circuit (1), and one screen portion is sequentially added for each pixel. The integration data (ID) is output to the white balance gain generation section (2). Next, the white balance gain (Bg) to be applied to the color signal (B) is lowered by the white balance gain generation unit (2) when the integration data (ID) is positive, and the color is lowered by the white balance gain when the integration data (ID) is negative. The white balance gain (Bg) is calculated based on the process of increasing the white balance gain (Bg) applied to the signal (B), and is output to the balance adjustment circuit (3). Next, the color signal (B) and the white balance gain (Bg) are converted into a balance adjustment circuit (3).
After being multiplied by the above, the result is output to the color difference matrix circuit (4). At this time, the color signals (R, G) output from the R [red] system and G [green] system circuits are input to the color difference matrix circuit (4), and these color signals (R, G, A color difference signal (RY, GY, BY) is generated each time based on the multiplication result data corresponding to B).

By adjusting the white balance gain as described above, the integral value of one color of the blue color difference signal (BY) converges to 0. Can be implemented.

[0009]

However, according to the video signal processing method according to the prior art, the color difference signals (R-Y, G-Y, B-) of each color are uniformly determined regardless of the color state of the screen.
Since the integration value of one screen of Y) is adjusted to be 0, the following problem occurs. For example, if a continuous landscape occupies many areas on the screen, such as taking a sunny landscape outdoors and capturing a blue sky in the upper half of the screen, half of the screen is blue. Since one color is occupied, if the integral of one screen of the blue color difference signal (BY) is obtained, the integral of (BY)> 0, and (BY) is obtained by the above-described video signal processing method. ))> 0, the process of reducing the white balance gain (Bg) applied to blue is performed.

That is, although the screen is not actually bluish, but the area where blue is continuous occupies most of the screen, the integrated value of the blue color difference signal (BY) is positive. In the state where the white balance is properly maintained, the above-described processing for lowering the white balance gain (Bg) by which the blue color is multiplied is performed. For this reason, the white balance gain (Bg) decreases and the white balance is lost, and the entire image becomes reddish or
There have been problems such as that the color of the blue sky appears whiter than it actually is, and that an image display with an appropriate color cannot be obtained.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional drawbacks, and detects a pixel in a portion of a screen where a color changes, and detects a color difference signal in the pixel of the portion where the color changes. Color change detection means (1) for selectively outputting only (CY)
1) and a color difference signal (C-
Y) for each screen, integrating means (12) for generating integration information (ID), and gain data based on the integration information (ID), and using the gain data as a color component of a video signal. A white balance adjusting means (13) for adjusting the white balance by multiplication is provided.

Then, in the first step, a pixel whose color has changed in the screen is detected, and only the color difference signal (C-Y) of the pixel whose color has changed is selectively obtained, and in the second step, According to the video signal processing method of integrating the acquired color difference signal (C-Y) for one screen and adjusting the white balance based on the result of the integration processing in the third step, even if the same color is continuously displayed on the screen, It is possible to obtain an image display of an appropriate color even in a case where a large area is occupied.

[0013]

According to the video signal processing apparatus of the present invention, as shown in FIG. 1, there are provided a color change detecting means (11), an integrating means (12) and a white balance adjusting means (13). . For example, based on the color difference signal (C-Y) of each pixel, the color change detecting means (11) detects a pixel of a portion where the color changes in the screen, and detects a color difference signal of the pixel of the portion where the color changes ( CY) is selected and output, and the color difference signal (CY) is integrated for each screen by the integration means (12) to generate integration information (ID). Based on the integration information (ID), white information is generated. Balance adjusting means (13)
Has adjusted the white balance. For this reason, it is possible to selectively integrate only the color difference signal (C-Y) of the portion where the color has changed in the screen.

Further, according to the video signal processing method according to the present invention, as shown in FIG. 2, in step P1, a pixel whose color has changed in the screen is detected, and a color difference signal (C−C−C) of the pixel whose color has changed is detected. Only Y) is selectively acquired, and step P2
Since the color difference signal (C-Y) acquired in step (1) is integrated for one screen and the white balance is adjusted based on the result of the integration processing in step P3, the color difference signal ( Only CY) can be selectively integrated. Therefore, since the integration process of the color difference signal (C-Y) is not performed in an area where the same color is continuous, an image in which the area where the same color is continuous occupies most of the screen. In the case where the white balance is properly obtained, the color difference signal (C-
The integrated value for one screen of Y) is a predetermined value, so that the white balance can be correctly adjusted, and an image display of an appropriate color can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A video signal processing apparatus and a video signal processing method according to an embodiment of the present invention will be described below with reference to the drawings. Note that the video signal processing device described below originally needs one for each of the three colors R, G, and B (or two colors for R and B), but in this embodiment,
Only B will be described, and G and R will not be described because they have the same configuration and operation.

The apparatus comprises a color change detection circuit (11) and an integration circuit (12), as shown in FIG. 3, and inputs a blue color difference signal (BY) to itself to change the color of the screen. This is an apparatus that outputs integrated data (ID) obtained by performing an integration process of a color difference signal (BY) only in a region to a white balance gain generation unit (not shown). Color change detection circuit (1
1) is an embodiment of the color change detecting means (11),
Only the color difference signal (BY) of the pixel whose color has changed is selectively output to the integration circuit (12). The color difference signal difference detection unit (11A), the comparison circuit (11B), and the AND circuit
It consists of a circuit (11C). Color difference signal difference detection unit (11
A) is an embodiment of a color information difference detection unit, which comprises first to third latch circuits (111 to 113), a subtractor (114), and an absolute value conversion circuit (115), From the color difference signal (BY) of the nth pixel (hereinafter referred to as the nth pixel),
After performing a subtraction process for subtracting the color difference signal (BY) of the (n-2) th pixel (hereinafter referred to as an (n-2) th pixel), the subtraction result is converted into an absolute value to be used as difference data (DD). The color difference signal (BY) of the n-th pixel is output to the AND circuit (11C) at the same time as being output to the comparison circuit (11B). The comparison circuit (11B) is an embodiment of the comparison means, and includes difference data (DD) and reference data (S
D), and when the difference data (DD) exceeds the reference data (SD), an integration permission signal (IA) of a high level [hereinafter referred to as “H”] is output to an AND circuit (11C).
And when the difference data (DD) does not exceed the reference data (SD), a low-level (hereinafter, referred to as “L”) integration enable signal (IA) is output to the AND circuit (11C). . The AND circuit (11C) selectively outputs the color difference signal (BY) of the n-th pixel to the integration circuit (12) based on the integration permission signal (IA), and outputs the integration permission signal (IA). When "H", the color difference signal (BY) of the n-th pixel is output to the integration circuit (12), and when "L", the color difference signal (BY) of the n-th pixel is output to the integration circuit (1).
This is a circuit that performs an operation of not outputting to 2).

The integration circuit (12) is an embodiment of the integration means, and integrates the color difference signal (BY) selectively output from the color change detection circuit (11) for one screen to obtain integration data ( ID) and outputs it to an external white balance gain generator (not shown). The white balance gain generation unit (not shown) uses a gain applied to B [red] when the integration data (ID), which is the integration value of one color difference signal (BY) for one screen, is positive, as in the related art. By lowering a certain white balance gain (Bg) and increasing the white balance gain (Bg) when the integration data (ID) is negative, the white balance gain (B−Y) converges to 0 so that the integrated value of the color difference signal (BY) converges to 0. B
g) adjustment device.

As described above, according to the video signal processing apparatus according to the embodiment of the present invention, the color difference signal (B-
Y), the color-change detection circuit (11) detects a pixel whose color has changed in the screen, selects only the color-difference signal (BY) of the pixel whose color has changed, and outputs the selected signal to the integration circuit (1).
According to 2), the color difference signal (BY) is integrated for each screen to generate integrated data (ID). For this reason, only the color difference signal (B-Y) in the portion where the color has changed in the screen is selectively integrated, and for example, the color difference signal (B-Y) is not integrated in a region where the same color continues. It becomes possible to do.

Hereinafter, a video signal processing method according to an embodiment of the present invention will be described with reference to the flowchart of FIG. 4 while supplementing the operation of the apparatus. First, in step P1 of the flowchart in FIG. 4, a process of acquiring the color difference signal (ND) of the n-th pixel and the color difference signal (Nd) of the (n-2) -th pixel is performed. At this time, the first latch circuit (111)
The color difference signal (Nd) of the (n-2) th pixel, the color difference signal of the (n-1) th pixel in the second latch circuit (112), and the color difference signal (Nd) of the (n-1) th pixel in the third latch circuit (113). Holds the color difference signal (ND) of the n-th pixel. That is, FIG.
As shown in the figure, the input of the second latch circuit (112) is connected to the output of the first latch circuit (111).
The input of the third latch circuit (113) is connected to the output of (12), respectively, and these are all color difference signals (B-
It operates in conjunction with a reference clock (CK) synchronized with Y). Therefore, the color difference signal (BY) input to the first latch circuit (111) is sequentially transmitted to the second latch circuit (112) and the third latch circuit (113) in conjunction with the reference clock (CK). The third latch circuit (11
If the color difference signal (ND) of the n-th pixel is held in (3), the second latch circuit (112) immediately before it holds the (n) -th pixel.
The color difference signal of the (n-2) th pixel is stored in the first latch circuit (111) immediately before the second latch circuit (112). Is held.

Next, in step P2, a process of acquiring difference data (DD) which is a difference between the color difference signal (ND) of the n-th pixel and the color difference signal (Nd) of the (n-2) -th pixel is performed. At this time, the color difference signal (Nd) of the (n-2) th pixel is subtracted from the first latch circuit (111), and the color difference signal (ND) of the nth pixel is subtracted from the third latch circuit (113). Container (11
4), and the subtractor (114) converts the color difference signal (ND) of the n-th pixel to the color difference signal (N) of the (n-2) th pixel.
A subtraction process for reducing d) is performed. Then the subtractor (11
The absolute value of the result of the subtraction by 4) is calculated by the absolute value conversion circuit (115), and the calculation result is output to the comparison circuit (11B) as difference data (DD).

Next, in step P3, the difference data (D
A determination process is performed to determine whether or not D) exceeds the reference data (SD). If it has exceeded (Yes), the process shifts to Step P4; otherwise (No), the process shifts to Step P7. This determination process is performed by the comparison circuit (11B). That is, a comparison process is performed between the reference data (SD) having a predetermined constant value and the difference data (DD). When the difference data (DD) exceeds the reference data (SD), “H” is set. The integration permission signal (IA) is output to the AND circuit (11C). If the integration permission signal (IA) is not exceeded, the "L" integration permission signal (IA) is output to the AND circuit (11C).

Next, in step P4, the color difference signal (ND) of the n-th pixel is obtained as integration data for integration processing for one screen, and integration processing is performed. At this time, the AND circuit (11
Since the color difference signal (ND) of the n-th pixel and the “H” integration permission signal (IA) are input to C), the n-th pixel is determined based on the “H” integration permission signal (IA). Is output to the integration circuit (12), and the color difference signal (ND) of the
According to 2), the color difference signal (ND) of the n-th pixel is integrated. When the "L" integration permission signal (IA) is input to the AND circuit (11C), the color difference signal (ND) of the n-th pixel is not output to the integration circuit (12), and the integration process is not performed. If the difference data (DD) does not exceed the reference data (SD), the color difference signal of the pixel is excluded from the integration processing.

Next, in step P5, an end confirmation process is performed. If the process can be ended (Yes), the process ends. If not (No), the process proceeds to step P6. Then, in step P6, 1 is added to n, and a transition process to the next pixel is performed. Similarly, in step P7, 1 is also added to n, and a transition process to the next pixel is performed. By sequentially repeating the above processing for the next pixel, the next pixel, and so on, integration of the color difference signal (BY) in a portion where the color difference signal (BY) has changed beyond a certain reference value is performed. The processing is performed for one screen. Thereafter, when the integrated value of the color difference signal is positive, the white balance gain (Bg) applied to B [red] is reduced, and when the integrated value is negative, the white balance gain (Bg) is increased. Is adjusted so that the integrated value of the color difference signal within the pixel converges to zero.

As described above, according to the video signal processing method according to the embodiment of the present invention, a pixel whose color has changed in a screen is detected, and a color difference signal (B−B) of the pixel whose color has changed is detected.
Y) is selectively obtained, and the color difference signal (BY) thus obtained is integrated with respect to one screen. For this reason, the color difference signal (BY) of the pixel in the region where the blue color is continuous is excluded from the integration process, and the integration process of the color difference signal (BY) at this pixel is not performed. If the color difference signal (B-Y) is correctly obtained, the integrated value of one color of the color difference signal (B-Y) becomes 0 and does not become positive, so that the process of lowering the white balance gain (Bg) is not performed, and the white balance is not broken.

According to the present embodiment, only the color difference signal of the pixel whose color changes is integrated with respect to one screen, but the present invention is not limited to this, and one screen is divided into a plurality of areas. Count the number of pixels that change color in that area.For example, perform integration processing in a region where the number of pixels that change color is large, and do not perform integration processing in a small region. The same effect can be obtained by a method of determining whether or not to perform the integration processing of the color difference signal. In this case, the output of the comparison circuit (11B) is received by the counter, and when the count value reaches a certain value, the color difference signal BY is supplied to the integration circuit (12).

In this embodiment, the color difference signal (B-
(Y) is an example of a color difference signal (C-Y), and the difference data (DD) is an example of a difference. Further, the reference data (S
D) is an example of a reference value, the integration permission signal (IA) is an example of a drive control signal, and the integration data (ID) is an example of integration information.

[0027]

As described above, according to the video signal processing apparatus of the present invention, it is possible to selectively integrate only the color difference signal (C-Y) of the portion where the color has changed in the screen. become. Further, according to the video signal processing method of the present invention, a pixel whose color has changed in the screen is detected, and only the color difference signal (C-Y) of the pixel whose color has changed is selectively obtained, and thus obtained. Since the processed color difference signal (C-Y) is integrated with respect to one screen and the white balance is adjusted based on the processing result, the color difference signal (C-Y) of a portion where the color has changed in the screen. By selectively integrating only the colors, it is possible to correctly adjust the white balance even in an image where the area where the same color is continuous occupies most of the screen, and display the image of the appropriate color Can be obtained.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a video signal processing device according to the present invention.

FIG. 2 is a principle diagram of a video signal processing method according to the present invention.

FIG. 3 is a configuration diagram of a video signal processing device according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a video signal processing method according to an embodiment of the present invention.

FIG. 5 is a configuration diagram of a video signal processing device according to a conventional example.

[Explanation of symbols]

 (11) Color change detecting circuit [Color change detecting means] (12) Integrating circuit [Integrating means] (13) White balance adjusting means (111) First latch circuit (112) Second latch circuit (113) Third (114) Subtractor (115) Absolute value conversion circuit (11A) Color difference signal difference detection section (11B) Comparison circuit [comparing means] (11C) AND circuit (circuit)

Claims (4)

(57) [Claims] A color change which detects a pixel at a boundary where a color changes in one screen, and selectively outputs only a color difference signal (C-Y) at a pixel of the portion where the color changes. Detection means (11);
An integrating means (12) for integrating the color difference signal (C-Y) from the color change detecting means (11) for each screen to generate integrated information (ID); And a white balance adjusting means (13) for adjusting the white balance by multiplying the gain data by a color component of the video signal. 2. A color change which detects a pixel at a boundary portion where a color changes in one screen and selectively outputs only a color difference signal (C-Y) at a pixel of the portion where the color changes. Detection means (11);
The color difference signal (C-Y) from the color change detection means (11) is integrated on a screen-by-screen basis to generate integration information (ID) based on the integration information (ID) and the integration information (ID). White balance adjustment means (13) for generating gain data and multiplying the gain data by the color component of the video signal to adjust white balance, and the color change detection means (11).
Is the difference (DD) between the color difference signals (CY) of the adjacent pixels.
And a drive control signal (IA) by comparing the difference (DD) with a reference value (SD).
Comparing means (11B) for generating the driving control signal (I
On the basis of A), the color difference signal (C-Y) is
2. A video signal processing device comprising: a gate circuit (11C) for outputting the signal to 2). 3. A pixel at a boundary portion where a color changes in one screen is detected, and a color difference signal (C−C) of a pixel whose color changes is detected.
Y) is selectively obtained, the obtained color difference signal (C-Y) is integrated with respect to one screen, and the mutual balance of each component of the video signal is adjusted based on the result of the integration processing. A video signal processing method characterized by the above-mentioned. 4. A boundary portion where a color changes within one screen by comparing color difference signals (CY) of adjacent pixels.
Detecting a pixel, the color difference signals of pixels the color saturation is changed (C
-Y) only, and the acquired color difference signal (C-Y) is integrated for one screen, and the mutual balance of the color components of the video signal is adjusted based on the result of the integration. A video signal processing method.