JPH089199A - Method and device for processing image pickup signal - Google Patents

Abstract

PURPOSE:To provide the method and device for processing image pickup signals in which aperture correction for a low level luminance signal is suppressed to enable the aperture correction without a sense of incongruity for a display processing image or the like. CONSTITUTION:A signal from a solid-state image pickup element 101 is separated into a luminance signal and a chrominance signal by a luminance signal/chrominance signal separator 105 and the separated luminance signal is given to a gamma correction circuit 114, a high pass filter 120, a gain adjustment circuit 121 and a base clip circuit 122, from which a luminance signal high frequency component YH subject to gain adjustment and noise elimination is obtained. On the other hand, the separated chrominance signal is given to a simultaneous processing circuit 106, a 1st matrix arithmetic circuit 107, a white balance circuit 108, a gamma correction circuit 109, and a 2nd matrix arithmetic circuit 110, in which arithmetic processing is conducted to obtain a color difference signal and the luminance signal and the luminance signal high frequency component YH is multiplied with a coefficient from a coefficient generating circuit 124 depending on the level of the luminance signal at a multiplier 123 and the result is added to the luminance signal whose phase is adjusted by a delay circuit 115 at an adder 116.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup signal processing device and an image pickup signal processing method using a solid-state image pickup device such as a CCD.

[0002]

2. Description of the Related Art A conventional image pickup signal processing apparatus is shown in FIG.
It is configured as shown in.

In FIG. 3, reference numeral 101 denotes a solid-state image pickup device such as a CCD, and the solid-state image pickup device 101 is provided with Ye, Mg, Cy, and G color filters as shown in FIG. 4 to 4, data for two lines are added and read out, and in the even field and the odd field, the data is vertically offset.

[0004]

[Equation 1] Mg + Ye = WR

[0005]

[Equation 2] G + Ye = GR

[0006]

[Equation 3] Cy + G = GB

[0007]

## EQU00004 ## Cy + Mg = WB The correlation double sampling circuit 102 is connected to the output side of the solid-state image sensor 101, and the output side of the correlation double sampling (CDS) circuit 102 automatically performs gain control. A gain control (AGC) circuit 103 is connected. On the output side of the automatic gain control circuit 103, a luminance signal / color signal separator 105 for separating a luminance signal component and a chrominance signal component (Y / C) by filtering is provided via an AD converter (AD) 104. It is connected.

The separated color signal C is input to the luminance signal / color signal separator 105, the synchronization circuit 106 for performing the synchronization processing of the color signal C component, and the separated luminance signal Y are input. A gamma correction circuit 114 for correcting non-linearity of conversion characteristics is connected in parallel with each other. On the output side of the synchronizing circuit 106, a first RGB signal is generated.
Is connected to the matrix calculation (MTX) circuit 107, and a white balance (WB) circuit 1 for balancing the reference white is provided on the output side of the first matrix calculation circuit (ATX) 107.
08 is connected.

A gamma correction (γ) circuit 109 is connected to the output side of the white balance circuit 108, and a second matrix operation (MTX) for generating a color difference signal is generated on the output side of the gamma correction circuit 109. ) Circuit 110 is connected.

A hue correction circuit 111 for performing hue correction is connected to the output side of the matrix calculation circuit 110.
The output side of the hue correction circuit 111 has a modulation (MOD) circuit 1
A DA converter (D / A) 113 is connected via 12 and the color signal Fc is output to the output side of the DA converter 113.

On the other hand, on the output side of the gamma correction circuit 114, an aperture correction signal processing section 119 for performing aperture correction signal processing of a luminance signal and a delay (DLY) circuit 11 are provided.
5 and 5 are connected in parallel with each other. In this aperture correction signal processing unit 119, a high pass filter (HPF) 120 for extracting high frequency components, a gain adjusting circuit 121 for adjusting gain, and a base clip (BC) circuit 122 for removing noise are connected in series. And the output side of the delay circuit 115 and the base clip circuit 1
An adder 116 is connected to the output side of 22.

The output side of the adder 116 is connected to a blanking signal adding circuit 117 for creating the state of the signal "L" corresponding to the blanking period, and the output side of the blanking signal adding circuit 117 is connected. DA converter (D / A) 11
8 is connected to the luminance signal F from the DA converter 118.
y is output.

The operation of the conventional image pickup apparatus having such a configuration will be described.

The solid-state image pickup device 101 reads out the added color signals WR, GR, GB and WB obtained by adding the color signals of two lines, as shown in equations 1 to 4. With respect to these added color signals, the correlated double sampling circuit 102
Double sampling processing for removing noise is performed, the gain is adjusted by the automatic gain control circuit 103, conversion into a digital signal is performed by the AD converter 104, and then the digital signal is converted into a luminance signal / color signal separator 105. Entered in.

Then, in the luminance signal / color signal separator 105, the digital signal is separated into a luminance signal component and a color signal component by filtering, the color signal component is fed to the synchronization circuit 106, and the luminance signal component is fed to the gamma correction circuit. It is input to 114.

In the synchronizing circuit 206, the addition color signals are calculated by the equations (5) to (7) to synchronize the CR, CB and YL components.

[0017]

[Equation 5] CR = WR-GB

[0018]

(6) CB = WB-GR

[0019]

## EQU00007 ## YL = WR + GB = WB + GR These components are arithmetically operated by the first matrix arithmetic circuit 107 based on the equation 8 to obtain RGB signals.

[0020]

[Equation 8] The RGB signals thus obtained are input to the white balance circuit 108, gain adjustment is performed to perform white balance to balance the reference white, and then the gamma correction circuit 109 performs non-linear conversion characteristic conversion. The correction is performed, and the gamma-corrected RGB signal is input to the second matrix operation circuit 110.

In the second matrix operation circuit 110, Yo = 0.3R + 0.59G + O. The color difference signal is calculated as 11B. The calculated color difference signal is
It is input to the hue correction circuit 111, and the hue correction circuit 111 corrects the hue of these color difference signals based on Expression 10.

[0022]

[Equation 9]

[0023]

[Equation 10] However, −1 ≦ a ≦ 1, −1 ≦ b ≦ 1 The color difference signal whose hue has been corrected in this way is modulated by the modulation circuit 112 and then converted into an analog signal by the DA converter 113 to obtain a color difference. It is output as signal Fc.

On the other hand, the luminance signal component separated by the luminance signal / color signal separator 105 is corrected by the gamma correction circuit 114 for the non-linearity of the conversion characteristic, and then the high pass filter of the aperture correction signal processing unit 119. The high frequency component YH is input to 120, and the high frequency component YH is extracted.
Is input to the gain adjusting circuit 121, and the degree of aperture is adjusted. Next, in the base clip circuit 122, noise removal is performed based on the input / output characteristics shown in FIG. In this way, the high frequency component YH for which gain adjustment and noise removal have been performed is input to the adder 116.

The adder 116 includes a gamma correction circuit 1
The luminance signal, which is gamma-corrected in 14 and the phase is adjusted in the delay circuit 115, is added to the high-frequency component YH for which gain adjustment and noise removal have been performed, and the deterioration of the resolution in the high-frequency band is corrected by edge enhancement. Aperture correction is performed. The signal for which the aperture correction has been completed in this way is input to the blanking addition circuit 117,
A blanking signal that creates the state of the signal "L" corresponding to the blanking period is added, converted into an analog signal by the DA converter 118, and output as the luminance signal Fy.

[0026]

In the above-mentioned conventional image pickup apparatus, the luminance signal component separated by the luminance signal / color signal separator 105 and the high frequency component YH of the luminance signal subjected to only gain adjustment and noise removal are used. Is added to perform aperture correction. For this reason, a constant level of aperture correction is performed irrespective of the level of the brightness signal, and the degree of aperture correction becomes too large for the brightness signal of a relatively low level, resulting in a sense of discomfort in the displayed processed image, for example. There was a problem that it would end up.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to suppress aperture correction for a low-level luminance signal so that a displayed processed image or the like does not feel uncomfortable. An object is to provide an image pickup signal processing device and an image pickup signal processing method capable of performing aperture correction.

[0028]

In order to achieve the above object, the invention according to claim 1 separates a signal from an image pickup device into a brightness signal component and a color signal component by a brightness signal / color signal separator. In the imaging signal processing device for independently processing and outputting the video luminance signal and the video color signal, the arithmetic means for arithmetically processing the color signal components separated by the luminance signal / color signal separator, Aperture correction means for performing aperture correction control of the brightness signal component separated by the brightness signal / color signal separator using the brightness signal obtained by the calculation processing of the calculation means. .

Preferably, the aperture correction means is
A correction value generating means for generating a correction value according to the level of the luminance signal obtained by the calculation processing of the calculating means, and correcting the separated luminance signal component with the correction value. The correction value generation means sets the correction value such that the aperture correction amount decreases when the level of the luminance signal obtained by the calculation processing of the calculation means is low.

Similarly, in order to achieve the above object, the invention according to claim 4 separates a signal from an image pickup device into a luminance signal component and a chrominance signal component, and independently processes them to obtain a video luminance signal. In the imaging signal processing method for outputting a video color signal, a calculation step of calculating the separated color signal component and an aperture correction control of the separated luminance signal component are obtained by the calculation processing of the calculation step. And an aperture correction step performed using the brightness signal.

Preferably, the aperture correction step includes a correction value generation step for generating a correction value according to the level of the luminance signal obtained by the calculation processing of the calculation step, and the correction value is separated by the correction value. It is characterized in that the brightness signal component is corrected, and the correction value is set to a value such that the aperture correction amount decreases when the level of the brightness signal obtained by the calculation processing of the calculation step is low. Is characterized by.

[0032]

According to the present invention, the signal obtained from the image pickup device is separated into the luminance signal component and the color signal component, the separated color signal component is arithmetically processed, and the luminance signal obtained by this arithmetic processing is used. Aperture correction control of the separated luminance signal component is performed. For example, the separated luminance signal component is corrected with a correction value corresponding to the level of the luminance signal obtained by the arithmetic processing, preferably so that the aperture correction amount decreases when the luminance signal level is low.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of the present embodiment. The same parts as those in FIG. 3 already described are designated by the same reference numerals, and FIG. 2 shows the input / output characteristics of the coefficient generating circuit of FIG. It is a characteristic diagram.

As shown in FIG. 1, in the present embodiment, a multiplier 123 is newly added to the aperture correction signal processing unit 119 in addition to the configuration of the conventional image pickup signal processing apparatus already described with reference to FIG. And a coefficient generation circuit 124 are provided, the output side of the base clip circuit 122 and the output side of the coefficient generation circuit 124 are connected to the input side of the multiplier 123,
The input side of the coefficient generation circuit 124 is connected to the matrix calculation circuit 110 to receive the luminance signal Yo,
Further, the output side of the multiplier 123 is different in that it is connected to one input terminal of the adder 116.

The coefficient generating circuit 124 of the present embodiment has the input / output characteristics as shown in FIG. 2, and when the luminance signal Yo input to the coefficient generating circuit 124 is higher than the predetermined level A, the coefficient generating circuit 124. Outputs a fixed value coefficient corresponding to a predetermined value 1. When the luminance signal Yo is smaller than A, the output coefficient value linearly changes in the range of 0 to 1 according to the input signal Yo value. This input / output characteristic may be written in the ROM and stored, or may be realized by hardware.

The configuration of the other parts of this embodiment is the same as that of the conventional image pickup apparatus already described with reference to FIG.
A duplicate description will be omitted.

The operation of this embodiment having such a configuration will be described with reference to FIG.

In this embodiment, the luminance signal Yo is input from the matrix operation circuit 110 to the coefficient generation circuit 124, and the coefficient is added from the coefficient generation circuit 124 based on the input / output characteristics of the coefficient generation circuit 124 shown in FIG. Supplied to the container 117.
That is, as described above, when the luminance signal Yo input to the coefficient generating circuit 124 is higher than the predetermined level A, the coefficient generating circuit 124 outputs a coefficient having a fixed value corresponding to the predetermined value 1, and the luminance signal Yo When Yo is smaller than A,
The output coefficient value linearly changes in the range of 0 to 1 according to the input signal Yo value.

Then, the high-frequency component YH, the gain of which is adjusted by the gain adjusting circuit 121 and the noise of which is removed by the base clip circuit 122, and the coefficient from the coefficient generating circuit 124 are multiplied by the multiplier 123, and the obtained multiplication value is obtained. Is the adder 11
6 is input.

For example, when the brightness signal Yo having a low brightness level (<A) is input to the coefficient generation circuit 124, the coefficient generation circuit 124 supplies a coefficient having a value smaller than 1 to the multiplier 123. The high frequency component Y in the multiplier 123
It is multiplied by H to reduce the latter level. Then, the high-frequency component YH whose level has been reduced causes the adder 11 to
The aperture correction is performed at 6, and when the brightness of the brightness signal Yo is low, the degree of the aperture correction is suppressed.
Therefore, even if the luminance of the luminance signal Yo is low, a natural processed image with no discomfort can be obtained.

In this manner, the aperture-corrected luminance signal is added with the blanking signal for creating the state of the signal “L” corresponding to the blanking period in the blanking signal adding circuit 117, and the DA converter 118. It is converted into an analog signal and output as a luminance signal Fy.

Since the other operations of this embodiment are the same as those of the conventional image pickup apparatus already described, the duplicate description will be omitted.

As the input / output characteristics of the coefficient generating circuit 124 shown in FIG. 2, two or more different input / output characteristics may be provided so that these can be selected. As described above, by changing the input / output characteristics, it is possible to adjust the suppression characteristic of the aperture correction and perform the optimum aperture correction.

As described above, according to this embodiment, the luminance signal Yo obtained by calculating the color signals (RGB signals) is calculated.
Is supplied to the coefficient generation circuit 124, the coefficient value according to the level of the brightness signal Yo is multiplied by the brightness signal high frequency component YH from the base clip circuit 123, and the obtained aperture correction component signal is supplied to the adder 116. Therefore, for a luminance signal of low luminance, the degree of aperture correction is suppressed, and a processed image having a natural feeling without any discomfort can be obtained. Further, since the luminance signal obtained by arithmetically processing the color signal does not contain a high frequency component, a certain amount of aperture suppression is performed on the low luminance high frequency luminance signal. It is possible to prevent the flickering of the screen that occurs.

[0046]

According to the present invention, the output signal of the image pickup device is separated into a luminance signal component and a color signal component, the separated color signal component is arithmetically processed, and the luminance signal obtained by this arithmetic processing is used. Aperture correction control of the separated luminance signal component is performed, and aperture correction for the luminance signal of low luminance is suppressed, so that a processed image having a natural feeling without any discomfort can be obtained. Further, the flickering of the screen due to the variation of the aperture amount is also prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an image pickup signal processing device of the present invention.

FIG. 2 is a characteristic diagram showing input / output characteristics of the coefficient circuit of FIG.

FIG. 3 is a block diagram showing a configuration of a conventional image pickup signal processing device.

FIG. 4 is an explanatory diagram showing an arrangement of color filters of the solid-state image sensor of FIG.

5 is a characteristic diagram showing input / output characteristics of the base clip circuit of FIG.

[Explanation of symbols]

 1 Solid-state image sensor 105 Luminance signal / color signal separator 106 Simultaneous circuit 107 First matrix operation circuit 110 Second matrix operation circuit 116 Adder 119 Aperture correction signal processor 120 High-pass filter 123 Multiplier 124 Coefficient generator circuit

Claims (6)

[Claims] 1. A signal from an image sensor is separated into a luminance signal component and a color signal component by a luminance signal / color signal separator,
In an image pickup signal processing device for independently processing and outputting a video luminance signal and a video chrominance signal, an arithmetic means for arithmetically processing the chrominance signal component separated by the luminance signal / color signal separator; An image pickup signal processing device, comprising: aperture correction means for performing aperture correction control of the brightness signal component separated by the color signal separator using the brightness signal obtained by the calculation processing of the calculation means. 2. The aperture correction means has a correction value generation means for generating a correction value according to the level of a luminance signal obtained by the arithmetic processing of the arithmetic means, and the luminance separated by the correction value. The image pickup signal processing device according to claim 1, wherein the signal component is corrected. 3. The correction value generation means sets the correction value so that the aperture correction amount decreases when the level of the luminance signal obtained by the calculation processing of the calculation means is low. The image pickup signal processing device according to claim 2. 4. An image pickup signal processing method for separating a signal from an image pickup device into a luminance signal component and a chrominance signal component and independently processing the signals to output a video luminance signal and a video color signal. A calculation step of calculating a color signal component, and an aperture correction control of the separated luminance signal component,
And an aperture correction step performed using the luminance signal obtained by the calculation process of the calculation step. 5. The aperture correction step includes a correction value generation step for generating a correction value according to the level of a luminance signal obtained by the calculation processing of the calculation step,
The image pickup signal processing method according to claim 4, wherein the separated luminance signal component is corrected with the correction value. 6. The correction value is set to a value such that the aperture correction amount decreases when the level of the luminance signal obtained by the calculation process of the calculation step is low. 4. The image pickup signal processing method according to item 4.