JP2000032479A - Video signal processing apparatus and video signal processing method - Google Patents

Abstract

(57) Abstract: A video signal processing device capable of effectively correcting a portion colored by a vertical correlation error and correcting a colored / non-colored boundary portion in a natural manner. I will provide a. A video signal processing apparatus for processing an output signal of a CCD image sensor having two horizontal transfer units and having R, G, and B primary color filters on pixels is provided.
The signals of the two upper and lower pixels having different spatial positions of the CD image sensor are simultaneously read out, and the coloring that occurs when an image of a subject having no correlation between the pixels is detected is detected, and a coloring detection signal corresponding to the coloring level is detected. A vertical correlation error detecting means 12 for outputting and a vertical correlation error correcting means 16 for correcting a color difference signal based on a coloring level of a coloring detection signal are provided.
The vertical correlation error can be corrected according to the degree of the error.

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 for processing a video signal output from a CCD image sensor and a video signal processing method, and more particularly to a method for correcting a vertical correlation error according to the degree of the vertical correlation error. is there.

[0002]

2. Description of the Related Art As a conventional color camera, a camera using a CCD image sensor having two horizontal transfer units for reading charges has been known.

This CCD image sensor uses RG for each pixel.
It has a primary color filter of B, and the filters are arranged as shown in FIG. In this sensor, as shown in FIG. 3, the line of each field is composed of a G column and an R / B column, and the electric charge of each pixel in the upper and lower columns is divided into two horizontal transfer units (1). And (2). That is, G is output from the horizontal transfer unit (1), and R is output from the horizontal transfer unit (2).
And B are output alternately in a time division manner for each pixel.

At this time, for example, when a black-and-white subject is photographed,
Coloring occurs at the edge position of the horizontal boundary between white and black.
The coloring that occurs when an image of a subject having no correlation between the upper and lower two pixels having different spatial positions of the CCD image sensor is called a vertical correlation error.

A vertical correlation error correction device for detecting and correcting such vertical correlation error is disclosed in Japanese Patent Application Laid-Open No. 9-840.
No. 30 are known.

As shown in FIG. 4, this apparatus comprises a vertical correlation error detecting section 42 for detecting a vertical correlation error from an RGB input signal 41, and converts the RGB input signal 41 into a composite signal comprising a luminance signal and a color difference signal. An RGB → YUV conversion section 44 for conversion and a vertical correlation error correction section 46 for correcting a vertical correlation error of the converted color difference signal 45 are provided.

As shown in FIG. 5, the vertical correlation error correction section 46 amplifies the color difference signal 45 with a gain (−X dB), and the coloring detection signal 43 output from the vertical correlation error detection section 42. And a selector 52 for selecting either the input color difference signal 45 or the color difference signal output from the amplifier 51 based on

The vertical correlation error detection section 42 of this device
The upper and lower two pixels having different spatial positions of the D image sensor are simultaneously and independently read out, and signal processing is performed with the same electrical phase, thereby detecting a difference between the two pixels. This difference corresponds to coloring that occurs when an image of a subject having no correlation between the two pixels is captured, that is, a vertical correlation error. The detected value is compared with a threshold value TH, and the following colored detection signal 43 is converted to a vertical correlation error. The error is output to the error correction unit 46. Coloring level <TH → 0 (non-colored part) TH ≦ coloring level → 1 (colored part)

On the other hand, the RGB → YUV conversion section 44
Of the luminance signal Y and the color difference signal RY
(V) and a BY (U) signal 45.

The vertical correlation error correction section 46 is provided with a coloring detection signal 43.
The vertical correlation error is corrected by performing gain control of the RY and BY signals based on

In the vertical correlation error correction section 46, taking RY as an example, an RY input signal 45 is amplified by an amplifier 51 with a predetermined gain (-X dB). The selector 52 selects the following signals based on the coloring detection signal 43, and obtains an output R-Yo47 in which the vertical correlation error has been corrected.

As described above, in this device, when the signal difference between the pixels arranged in the vertical direction of the CCD image sensor is large,
Assuming that a vertical correlation error has occurred, the gain of the color difference signal is controlled to correct the image so that it looks natural.

[0013]

However, in the conventional vertical correlation error correction device, the coloring detection signal is colored and uncolored.
Since there is a distinction between stages and the selection of whether or not to correct the vertical correlation error, it is necessary to make corrections on the same line, for example, when photographing a subject where the boundary between white and black is oblique. If there is a pixel to be corrected and a pixel that does not need correction, if the value of X is increased to increase the effect of correction, the boundary between the corrected part and the part not to be corrected becomes unnatural, and conversely, If the value of X is reduced in order to make the boundary portion natural, there is a problem that the correction effect of the portion completely colored by the vertical correlation error is reduced.

The present invention is to solve such a conventional problem, and can effectively correct a portion colored by a vertical correlation error. It is an object of the present invention to provide a video signal processing device capable of performing correction in various forms and a video signal processing method thereof.

[0015]

Therefore, according to the present invention, the vertical correlation error detecting means outputs a coloring detection signal corresponding to the coloring level, and performs gain control on the color difference signal according to the coloring level. .

For this reason, a large correction effect appears in a portion completely colored by the vertical correlation error, and a correction is made at a boundary between colored and non-colored portions so that the image looks natural with a small amount of correction. Done.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention processes output signals of a CCD image sensor having two horizontal transfer units and having R, G, and B primary color filters on pixels. In the video signal processing device, the signals of the two upper and lower pixels having different spatial positions of the CCD image sensor are simultaneously read out, and the coloring that occurs when an image of an object having no correlation between the pixels is detected is detected. Vertical correlation error detection means for outputting a corresponding coloring detection signal,
Vertical correlation error correction means for correcting the color difference signal based on the coloring level of the coloring detection signal is provided, and the vertical correlation error can be corrected according to the degree of the error.

According to a second aspect of the present invention, the vertical correlation error detecting means sets the coloring level to a plurality of thresholds TH _n (n = 1,
2, compared with ‥), is obtained by outputs a colored detection signal corresponding to a range of TH _n-1 ≦ coloring level <TH _n, it is possible to partition the colored level.

According to a third aspect of the present invention, there is provided a video signal processing method for processing an output signal of a CCD image sensor having two horizontal transfer units and having R, G, and B primary color filters on pixels. The signals of the two upper and lower pixels having different spatial positions of the image sensor are simultaneously read out, and the coloring that occurs when an image of an object having no correlation between the pixels is detected. The higher the level of the coloring, the greater the attenuation. The gain control of the color difference signal is performed so that the effect of the correction is large in a completely colored portion, and the correction is performed so as not to be unnatural at a colored / non-colored boundary portion.

According to a fourth aspect of the present invention, the classification of the coloring level and the amount of attenuation are set according to the use of the camera incorporating the CCD image sensor or the scene to be photographed. An effective correction can be made by setting an appropriate value according to the use or the shooting scene.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The video signal processing device according to the embodiment of the present invention comprises:
As shown in FIG. 1, a vertical correlation error detection unit 12 that detects a vertical correlation error from an RGB input signal 11 and outputs a color detection signal 13 corresponding to a color level, and converts a RGB input signal 11 into a luminance signal and a color difference RGB → YUV converter 14 for converting to signal
And a vertical correlation error correction unit 16 that controls the gain of the converted color difference signal 15 in accordance with the coloring level represented by the coloring detection signal 13.

Further, as shown in FIG. 2, the vertical correlation error correction section 16 converts the color difference signal 15 into a gain (−X ₁ dB) (−X ₂ d).
B) Amplifiers 21 and 23 that amplify each of (−X ₃ dB)
And the coloring detection signal output from the vertical correlation error detection unit 12.
13 based on the input color difference signal 15 or amplifiers 21 and 23
Select the color-difference signal amplified in and select R-Yo or B-Yo
And selectors 22 and 24 for outputting the signals as 17.

The vertical correlation error detecting section 12 of this device
The upper and lower two pixels having different spatial positions of the D image sensor are simultaneously and independently read out, and signal processing is performed with the same electrical phase, thereby detecting a difference between the two pixels.
This difference corresponds to the colored (i.e. vertical correlation error) which occurs when an image correlation is not subject between the two pixels, comparing the detected value with a plurality of threshold values TH _n, the size of the coloring level In response to this, the next value is output to the vertical correlation error correction unit 16 as the coloring detection signal 13. Colored Level <TH ₀ → ₀ TH ₀ ≦ colored Level <TH ₁ → ₁ TH ₁ ≦ colored Level <TH ₂ → ₂ TH ₂ ≦ colored Level _{→ 3 (TH 0 <TH 1} <TH 2)

On the other hand, the RGB → YUV conversion unit 14
Of the luminance signal Y and the color difference signal RY
(V) and a BY (U) signal 15.

The vertical correlation error correction section 16 is provided with a coloring detection signal 13.
RY and BY based on the magnitude of the coloring level of
The vertical correlation error is corrected by performing signal gain control.

In the vertical correlation error correction section 16, taking RY as an example, the amplifier 21 converts the RY input signal 15 into gains (-X ₁ dB), (-X ₂ dB) and (- amplified with X ₃ dB). The selector 22 selects the following signal based on the coloring detection signal 13 and sets the selected signal as an output R-Yo17.

Here, the gain _Xn is in the relationship of 0 ≦ X ₁ ≦ X ₂ ≦ X ₃ , and the effect of correction increases as the degree of coloring increases.

As a result, the luminance signal of the part which is completely colored due to the vertical correlation error is greatly attenuated, while the effect of correcting the colored / non-colored boundary is reduced, and the unnatural luminance at the boundary is corrected. Is gone.

In this embodiment, the color detection signal is quaternized.
The more the value, the smoother the image.

Further, the threshold value TH _n and gain X _n a camera application, by setting an appropriate value according to the scene, it is possible to obtain an effective compensation.

[0032]

As is apparent from the above description, in the video signal processing apparatus and the video signal processing method of the present invention, the vertical correlation error coloring detection signal is multi-valued, and the vertical correlation error Since the correction is performed, a large correction effect is obtained in a portion that is completely colored due to the vertical correlation error, and the degree of correction is small at the boundary between the colored portion and the non-colored portion, so that a smooth natural Can be corrected to the image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a video signal processing device according to an embodiment;

FIG. 2 is a block diagram illustrating a configuration of a vertical correlation error correction unit in the video signal processing device according to the embodiment;

FIG. 3 shows a filter arrangement of a conventional CCD image sensor;

FIG. 4 is a block diagram showing a configuration of a conventional vertical correlation error correction device.

FIG. 5 is a block diagram showing a configuration of a vertical correlation error correction unit in a conventional vertical correlation error correction device.

[Explanation of symbols]

 11, 41 RGB input signal 12, 42 Vertical correlation error detector 13, 43 Coloring detection signal 14, 44 RGB → YUV converter 15, 45 Y, RY, BY signal 16, 46 Vertical correlation error corrector 17, 47 Corrected Yo, R-Yo, B-Yo signals 21, 23, 51 Amplifiers 22, 24, 52 Selector

Continuation of the front page (72) Inventor Yuichi Takenaga 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa F-term in Matsushita Communication Industrial Co., Ltd. 5C065 AA01 BB19 CC01 CC03 DD09 EE05 EE06 GG15 GG50

Claims (4)

[Claims] 1. A video signal processing apparatus for processing an output signal of a CCD image sensor having two horizontal transfer units and having R, G, and B primary color filters on pixels, the spatial position of the CCD image sensor. Simultaneously read the signals of the upper and lower two pixels different from each other, and detect the coloring that occurs when an image of a subject having no correlation between the pixels is detected.
Video signal processing, comprising: a vertical correlation error detecting means for outputting a coloring detection signal corresponding to the coloring level; and a vertical correlation error correcting means for correcting a color difference signal based on the coloring level of the coloring detecting signal. apparatus. 2. The vertical correlation error detecting means compares the coloring level with a plurality of thresholds TH _n (n = 1, 2, ‥), and according to a range of TH _{n -1} ≦ coloring level <TH _n . The video signal processing device according to claim 1, wherein the video signal processing device outputs the coloring detection signal. 3. A video signal processing method for processing an output signal of a CCD image sensor having two horizontal transfer units and having R, G, and B primary color filters on pixels, the spatial position of the CCD image sensor. The signals of the upper and lower two pixels that are different from each other are simultaneously read out, and the coloring that occurs when an image of a subject having no correlation between the pixels is detected is detected. A video signal processing method for correcting a vertical correlation error, wherein the video signal processing is performed by gain control. 4. The video signal processing method according to claim 3, wherein the classification of the coloring level and the amount of attenuation are set according to a use of a camera incorporating the CCD image sensor or a scene to be photographed. .