JP3903772B2 - Image processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus that has a communication function and is suitable for use in a video communication device that enables communication of a captured video signal through the Internet. Specifically, the difference in characteristics between the photographed video signal and the video signal to be communicated is corrected so that good display can be performed for both video signals.
[0002]
[Prior art]
For example, an image processing apparatus used in a video communication device that enables video signals captured by a digital video camera to communicate via the Internet, for example, has been implemented. In such an image processing apparatus, when displaying a video signal shot by a digital video camera or the like and a video signal communicated via the Internet or the like on a display panel or the like, the gain control of the luminance signal or the chroma signal is controlled. Adjustment of gain and hue, and processing for γ correction are performed.
[0003]
[Problems to be solved by the invention]
However, for example, a video signal communicated via the Internet has a sampling frequency ratio when converting from an analog signal to digital, and the luminance signal (Y) is four times as high as 3.375 [MHz]. The two color difference signals (C _R , C _B ) are one time, so-called 4: 1: 1. This is because the resolution of the color difference signal is lower than the 4: 2: 2 ratio used for digital conversion of a standard video signal, and this causes problems such as color blurring in the displayed image.
[0004]
That is, in FIG. 7, for example, when the characters “and” and the background are colored in different colors, the color of the boundary portion between the characters and the background oozes out from each other. What is to be displayed as shown in FIG. 7 is a display in which mutual colors ooze as shown in FIG. For this reason, when the color is dark and the number of strokes of characters is large, interpretation may be difficult. Such an obstacle is remarkable especially when the shape of the display panel is small, and there is a risk of impairing the commercial value.
[0005]
In addition, for example, in the case of a so-called menu screen as shown in FIG. 8, when images of transmission (Send), reception (Receive), and address (Address) are switched to each other and displayed, the gain of the luminance signal is displayed in the normal video signal display. Since the automatic control means works, the color intensity changes momentarily at the time of switching, which may give the user an unnatural impression. That is, such a menu screen is originally displayed stably, and it is unnatural to change such a stable display.
[0006]
This application has been made in view of the above points, and the problem to be solved is that, in the conventional apparatus, for example, when a video signal communicated through the Internet is displayed, color blur or the like is displayed on the image. There is a risk that a failure may occur, and when the image is switched on a so-called menu screen or the like, the darkness of the color changes momentarily, giving the user an unnatural impression.
[0007]
[Means for Solving the Problems]
For this reason, in the present invention, at least the luminance signal and chroma signal gain control means and the gamma correction means for forming the video signal are provided, and the correction value of each means for the video signal having characteristics different from the standard. Is set to a value different from the standard. According to this, for example, when displaying a video signal through the Internet, the difference in the characteristics of the standard and communicated video signal is corrected. Good display can be performed for both video signals.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
That is, in the present invention, an image processing apparatus having a video signal display function and a video signal communication function, and means for automatically controlling the gain of a luminance signal forming a video signal, and a chroma signal forming a video signal Means for adjusting the gain and hue, means for performing gamma correction of the three primary color signals formed from the video signal, first setting means for setting correction values of each means for at least a standard video signal, and a standard Is provided with second setting means for setting the correction value of each means for video signals having different characteristics. When displaying the video signal supplied through the communication function, the second setting means is used to display each of the means. A correction value is set.
[0009]
Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of an image processing apparatus to which the present invention is applied.
[0010]
In FIG. 1, a digital luminance signal forming a video signal is supplied to an input terminal 1. The luminance signal from the input terminal 1 is supplied to a luminance signal automatic gain control (YAGC) circuit 3 through a luminance saturation detection (YZRD) circuit 2 that detects saturation of the luminance signal. In the automatic gain control circuit 3, the input luminance signal is supplied to the multiplier 31, and the signal detected by the detector 32 is supplied to the multiplier 31 through the gain setting means 33 to automatically control the luminance signal. Is done.
[0011]
The input terminal 4 is supplied with a digital chroma signal forming a video signal. The chroma signal from the input terminal 4 is supplied to a chroma signal adjustment (CHIS) circuit 5 that adjusts the gain and hue of the chroma signal. In the chroma signal adjustment circuit 5, the input chroma signal is supplied to the hue correction means 52 through the delay correction means 51 for correcting the delay amount with the luminance signal, and the two color difference signals are separated by the hue correction means 52. It is taken out through the gain control amplifier 53.
[0012]
The chroma signal from the chroma signal adjustment circuit 5 is supplied to a signal insertion (CGSW) circuit 6 for inserting a synchronization signal and a blanking signal and for displaying a screen. The luminance signal from the automatic gain control circuit 3 is supplied to the signal insertion circuit 6 through an automatic picture control (APC) circuit 7 that corrects the contrast of the luminance signal. The luminance signal and the chroma signal (two color difference signals) from the signal insertion circuit 7 are supplied to the matrix circuit 8 to extract the three primary color signals.
[0013]
Further, the three primary color signals are supplied to the γ correction circuit 9. In this γ correction circuit 9, for example, for each of the three primary color signals, the original signal is supplied to the adder 91, and the gain and the level for switching the gain can be set at different positions, respectively. A signal through 93 is supplied to the adder 91. As a result, γ correction is performed with the correction curve being variable in two places, and this correction signal is taken out through a white level limiting (WHlim) circuit 94.
[0014]
The three primary color signals from the γ correction circuit 9 are supplied through a digital signal gain control (DAGC) circuit 10 to a display panel (not shown), for example, for three-channel digital / analog conversion (DAC). It is supplied to the circuit 11. In this way, the digital luminance signal and the chroma signal supplied to the input terminals 1 and 4 are subjected to gain control, hue adjustment, γ correction and the like from the digital / analog conversion circuit 11 for supplying a signal to the display panel. It is taken out.
[0015]
In this apparatus, the luminance signal automatic gain control (YAGC) circuit 3, the chroma signal adjustment (CHIS) circuit 5 for adjusting the gain and hue of the chroma signal, and the γ correction circuit 9 are controlled, adjusted and corrected. The setting is performed through the signal lines 12A to 12C as described below, for example.
[0016]
That is, in FIG. 2, for example, the clock signal SCK as shown in FIG. 2A is supplied to the signal line 12A for each vertical synchronization period of the video signal, and the data as shown in FIG. Signal SI is provided. For example, a control signal CS as shown in FIG. 2C is supplied to the signal line 12C. The data signal SI is provided with 8 bits for each clock signal SCK, and the respective control data is set in the circuits 3, 5 and 9 during the low potential period of the control signal CS.
[0017]
Further, as the control data provided in the data signal SI, for example, data D1, D2,... Are sequentially provided starting from the vertical synchronization signal. For example, the data D20 to D34 are set in the circuits 3, 5, and 9 described above. Used for. Accordingly, in each of the circuits 3, 5, 9, the clock signal SCK is counted starting from the vertical synchronization signal, and the data D 20 -D 34 are fetched according to the count value, and the settings of the circuits 3, 5, 9 are performed. It is what is said.
[0018]
These data D20 to D34 are provided with setting values as shown in the table of FIG. That is, in FIG. 3, the setting value of the gain of the luminance signal is provided in bits 0 to 7 of the data D20. Further, a variable value of the brightness of the luminance signal is provided in bits 0 to 7 of the data D21. Further, the gain control limiter setting value is provided in bits 0 to 3 of the data D22, and the lower detection level setting value of gain control is provided in bits 4 to 7.
[0019]
In addition, a set value of a gain control level is provided in bits 0 to 4 of data D23, and a set value of an upper detection level of gain control is provided in bits 5 to 7. Furthermore the bit 0-5 data D24 set value of the gain of the chroma C _R signal is provided, control bits change off of the slope of the gain control to the switching, the bit 7 of the frequency f0 of the aperture correction bit 6 Is provided. The set value of the gain of the chroma C _B signal is provided to bit 0-5 of the data D25.
[0020]
Furthermore a hue set value of chroma C _R signal to the bit 0-5 of the data D26, 4 vertical interval of the gain control to a set value and the bit 7 of the hue of the chroma C _B signal bits 0-5 (4V) On / off control bits for average detection are alternately provided. In addition, bits 0 to 6 of data D27 and bits 0 to 5 of data D28 are provided with setting values for upper and lower break points of γ correction, and bits 0 to 5 of data D29 and bits 0 to 5 of data D30 are set. Are provided with set values for the upper and lower gains of γ correction.
[0021]
A set value of the aperture correction gain is provided in bits 0 to 3 of the data D31. Further, a set value for white level restriction for γ correction is provided in bits 0 to 4 of the data D32. Then, bits 0 to 3 of the data D33 are provided with a set value on the low side of user-controlled brightness, and bits 4 to 7 are set on the high side. Further, bits 0 to 3 of the data D34 are provided with a low-side setting value of the user-controlled chroma signal, and bits 4 to 7 are provided with a high-side setting value.
[0022]
Further, the values of these data, for example, values stored in advance in setting means such as an EEPROM are sequentially read out in accordance with the clock signal SCK starting from the vertical synchronization period, and the signal line 12B as data D20 to D34 of the data signal SI. It will be sent to. For standard video signals, for example, values as shown in column A of FIG. 3 are stored in, for example, EEPROM page C addresses D1 to E0, and these values are sequentially read and set.
[0023]
On the other hand, for example, for a video signal supplied by communication, values such as those shown in column B of FIG. 3 are stored in page 8 addresses 9A to A2 of the EEPROM, for example. In this case, however, the value in which the address is blank is one in which the set value does not change between the standard and communication video signals. In addition, items having the same values in the A column and the B column can be changed as necessary, although they are not changed in the present embodiment. These values are sequentially read and set.
[0024]
For example, for the video signal supplied by communication, the values of the page C addresses D1 to E0 of the EEPROM are sequentially read and set in the same manner as the standard video signal. As shown by [→] in the figure, the values of the page 8 addresses 9A to A2 are read and set. That is, the values of the page 8 addresses 9A to A2 are read and set for the data D20, D22 to D25, and D27 to D30, respectively.
[0025]
In this way, for example, the standard video signal and the video signal supplied by communication are stored in the respective setting means (for example, page 8 addresses 9A to A2 and page C addresses D1 to E0 of the EEPROM). The values are read out and appropriate settings can be made for each. These settings correct the difference in the characteristics of the respective video signals, so that good display can be performed for both video signals.
[0026]
More specifically, for example, the configuration of the γ correction circuit 9 of FIG. 1 is as shown in FIG. Since the circuit configuration of FIG. 4 is well known, detailed description is omitted. That is, in this circuit, for example, when an input signal as shown in FIG. 5A is supplied, an output signal as shown in FIG. 5B is taken out. For example, by changing the values of the data D27 and D29 described above, the values of the γ1 level and the γ1 gain indicated by the bold arrows in FIG. 4 are arbitrarily set.
[0027]
In this way, the γ correction characteristics can be changed. In this case, the γ correction characteristics are changed as indicated by broken lines (1) and (2) in FIG. 5B. Here, when the characteristic of γ correction is moved to the high luminance side, for example, as indicated by the broken line (1), the entire screen becomes bright and the occurrence of color blur becomes inconspicuous. Further, by reducing the gain of the chroma signal in the chroma signal adjustment (CHIS) circuit 5, the occurrence of color blur can be made less noticeable.
[0028]
That is, in the conventional apparatus, for example, when the character and the background are colored in different colors, the color of the boundary portion between the character and the background oozes out, so that the number of strokes of the character is dark and dark. In many cases, interpretation has become difficult, but such a situation can be resolved. Such an obstacle is remarkable particularly when the shape of the display panel is small, but by eliminating this, the value of these products can be improved.
[0029]
The configuration of the automatic gain control (YAGC) circuit 3 in FIG. 1 is as shown in FIG. Since the circuit configuration of FIG. 6 is well known, detailed description thereof is omitted. In this circuit, for example, the automatic gain control level indicated by the thick arrow in FIG. 6 is set to 0 to 2 times according to the set value of the gain control level of the data D23. Then, the gain control of the automatic gain control (YAGC) circuit 3 is turned off by setting the set value to 0 times, for example.
[0030]
In this way, the level of automatic gain control of the luminance signal can be changed. In this case, for example, when gain control is turned off, so that images are switched and displayed on a so-called menu screen or the like, the automatic gain control means works and the color intensity is instantaneously changed at the time of switching. The risk of changing and giving an unnatural impression to the user can be eliminated, and the product value can be improved by eliminating the unnaturalness.
[0031]
Therefore, in this embodiment, at least a luminance signal and chroma signal gain control means for forming a video signal and a gamma correction means are provided, and the correction value of each means is set for a video signal having characteristics different from the standard. By setting it to a value different from the standard, for example, when displaying a video signal via the Internet, the difference in the characteristics of the standard and communicated video signal is corrected, and for which video signal Can also provide good display.
[0032]
As a result, in conventional devices, for example, when displaying a video signal communicated via the Internet, a failure such as color blur occurs in the image, and the color intensity changes momentarily when switching the image on a so-called menu screen or the like. However, according to the present invention, these problems can be easily solved, which may give a user an unnatural impression.
[0033]
That is, in the above-described embodiment, for example, a video signal in which the ratio of the luminance signal (Y) and the two color difference signals (C _R , C _B ) communicated via the Internet is 4: 1: 1 and the standard 4: 2: When the video signal of 2 is displayed on a display panel or the like, the difference in the characteristics of the video signal regarding the control of the luminance signal gain, the adjustment of the gain and hue of the chroma signal, and the processing for γ correction, etc. Is corrected so that a good display can be performed for both video signals.
[0034]
Thus, according to the above-described image processing apparatus, an image processing apparatus having a video signal display function and a video signal communication function, the means for automatically controlling the gain of the luminance signal forming the video signal, and the video signal Means for adjusting the gain and hue of the chroma signal to be formed; means for performing γ correction of the three primary color signals formed from the video signal; and first setting means for setting correction values of the respective means for at least a standard video signal And a second setting means for setting the correction value of each means for a video signal having characteristics different from the standard, and the second setting means is used when displaying the video signal supplied through the communication function. By setting the correction value of each means, for example, when displaying a video signal through the Internet, the difference in the characteristics of the standard and communicated video signal is corrected, and either video signal is corrected. One in which it is possible to perform even better display for.
[0035]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0036]
【The invention's effect】
Therefore, according to the invention of claim 1, there is provided an image processing apparatus having a video signal display function and a video signal communication function, and means for automatically controlling a gain of a luminance signal forming the video signal;
Means for adjusting the gain and hue of the chroma signal forming the video signal, means for performing gamma correction of the three primary color signals formed from the video signal, and the sampling frequency of the luminance signal and the two color difference signals forming the chroma signal The ratio of the sampling frequency between the first setting means for setting the correction value of each means for the first video signal whose ratio is the first ratio and the two color difference signals forming the luminance signal and the chroma signal is the first. And a second setting means for setting a correction value of each means for a second video signal smaller than a ratio of 1. When displaying a video signal supplied through a communication function, the second setting means is The chroma signal gain in the means for adjusting the gain and hue of the chroma signal is set lower than the setting in the first setting means, and the γ curve in the means for performing γ correction of the three primary color signals is set to the first setting. Setting by means Ri by which is adapted to set a correction value of each unit to move to the high brightness side, for example in case of displaying the video signal through the Internet, to correct the difference in characteristics of the video signal standards and communication Te, also can make excellent display for both video signals, is shall be able to not particularly noticeable occurrence of color bleeding.
[0038]
Further, according to the invention of claim 2 , when the video signal supplied through the communication function is displayed by the display function, the gain is automatically controlled by the means for automatically controlling the gain of the luminance signal by the second setting means. By stopping the operation, the fear of giving an unnatural impression to the user can be solved.
[0039]
As a result, in conventional devices, for example, when displaying a video signal communicated via the Internet, a failure such as color blur occurs in the image, and the color intensity changes momentarily when switching the image on a so-called menu screen or the like. However, according to the present invention, these problems can be easily solved, which may give a user an unnatural impression.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of an image processing apparatus to which the present invention is applied.
FIG. 2 is a diagram for explaining the operation;
FIG. 3 is a table for explanation.
FIG. 4 is a specific circuit configuration diagram of a main part of an image processing apparatus to which the present invention is applied.
FIG. 5 is a diagram for explaining the operation;
FIG. 6 is a specific circuit configuration diagram of a main part of an image processing apparatus to which the present invention is applied.
FIG. 7 is a diagram for explaining a conventional technique.
FIG. 8 is a diagram for explaining a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Luminance signal input terminal, 2 ... Luminance saturation detection (YZRD) circuit, 3 ... Luminance signal automatic gain control (YAGC) circuit, 31 ... Multiplier, 32 ... Detector, 33 ... Gain setting means, 4 ... Chroma Signal input terminal, 5 ... Chroma signal adjustment (CHIS) circuit, 51 ... Delay correction means, 52 ... Hue correction means, 53 ... Gain control amplifier, 6 ... Signal insertion (CGSW) circuit, 7 ... Automatic picture control (APC) Circuit: 8 ... Matrix circuit, 9 ... γ correction circuit, 91 ... Adder, 92 ... γ1 circuit, 93 ... γ2 circuit, 94 ... White level limiting (WHLim) circuit, 10 ... Digital signal gain control (DAGC) circuit, 11: Digital / analog conversion circuit, 12A to C ... Signal line

Claims (2)

An image processing apparatus having a video signal display function and a video signal communication function,
Means for automatically controlling the gain of the luminance signal forming the video signal;
Means for adjusting the gain and hue of a chroma signal forming the video signal;
Means for performing γ correction of the three primary color signals formed from the video signal;
First setting means for setting correction values of the respective means for a first video signal in which the ratio of the sampling frequency between the luminance signal and the two color difference signals forming the chroma signal is a first ratio ;
Second setting means is provided for setting a correction value of each means for a second video signal in which the ratio of the sampling frequency between the luminance signal and the two color difference signals forming the chroma signal is smaller than the first ratio. ,
When displaying the video signal supplied through the communication function ,
Using the second setting means ,
The gain of the chroma signal in the means for adjusting the gain and hue of the chroma signal is made lower than the setting in the first setting means, and the γ curve in the means for performing γ correction of the three primary color signals is shown in the first An image processing apparatus , wherein the correction value of each means is set so as to move to a higher luminance side than the setting by the setting means . When displaying the video signal supplied through the communication function with the display function,
By the second setting means,
The image processing apparatus according to claim 1, wherein the automatic gain control by the means for automatically controlling the gain of the luminance signal is stopped.

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