JPS6331387A - Video camera - Google Patents

Abstract

PURPOSE:To effectively avoid the occurrence of underachromatized or over- achromatized horizontal scanning lines by generating a control signal for achromatizing operation based on the chrominance signal components of an image pickup signal. CONSTITUTION:The chrominance signal components C1X and C2X outputted from 1H delay lines 14 and 15 are given to the maximum value selecting circuit 26 of an achromatizing circuit 25, and a higher color signal level is delected, and a slicing circuit 27 slices a maximum value selecting signal MAX with a prescribed slice level to generate a control signal CON for achromatization, and this signal is given to a gain control circuit 22. The circuit 22 varies the gain to a coming carrier chrominance signal CAR to perform the achromatizing operation. Consequently, the carrier chrominance signal CAR and the control signal CON are synchronized with each other to effectively avoid the occurrence of over-achromatization or underachromatization.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video camera, and more particularly, to a color video camera using a solid-state I-imaging element, in which chroma suppression (chroma suppression) can be appropriately controlled. It is.

B. Summary of the Invention The present invention relates to a video camera in which three primary color signals of a predetermined horizontal scanning line are obtained by performing vertical correlation calculations on imaging signals of a plurality of horizontal scanning lines. By forming the control signal for the achromatic operation based on the color signal component of the imaging signal for the line, it is possible to effectively avoid the occurrence of horizontal scanning lines with insufficient or excessive achromatization. This is what I did.

C Conventional technology In a color video camera, if there is a high-brightness part in the subject, such as a spotlight, the signal level exceeds the dynamic range of the imaging element and signal processing circuit and becomes saturated. In this case, if all color signal components are saturated at the same time, the white balance will not be disrupted, but if, for example, only the green signal is saturated and the red and blue signals are not, the color is originally achromatic (white). The high-brightness areas where they should be are colored magenta.Therefore, color video cameras are equipped with an achromatic chroma suppressor circuit that makes the high-brightness areas achromatic to prevent inappropriate coloring.

In order to more effectively perform achromatization using such an achromatic circuit, a control signal for achromatization is not formed from a carrier color signal, but is generated based on color signal components obtained from an f-stone image element (imager). A device in which the structure is formed has already been proposed (Japanese Patent Application No. 61-30234).

Problems to be Solved by the Invention Incidentally, so-called checkered coating as shown in FIG. 3 is employed in video cameras having a small number of pixels as a color filter coating for each imaging cell of an imager. In this checkered coating,
Each horizontal scanning line...L (N-1), LN
, L (N+1)... are two color signal components (2
Therefore, it is not possible to obtain three primary color signals for each horizontal scan line by simply taking out the I stone image signal.

Therefore, in a video camera having an imager with this checkered coating, the color signal components (for example, blue signal B) of the upper and lower horizontal scanning lines (for example, L (N-1), L (N+1)) are subjected to vertical correlation calculation. (eg, by averaging) to obtain the missing color signal component in the horizontal scanning line (eg, LN). Therefore, the horizontal scanning line for the imaging signal from the imager and the horizontal scanning line for the three primary color signals R, G, and B obtained by vertical correlation calculation (that is, the horizontal scanning line for the carrier color signal) are vertically Since it is delayed to perform the correlation calculation, the difference will be due to the delay.

When trying to apply the proposed technical concept of obtaining control signals for achromatization based on color signal components from an imager to a video camera that uses a checkered coating using an existing IC (integrated circuit), The horizontal scanning line for the control signal becomes the horizontal scanning line for the imaging signal.

Therefore, the horizontal scanning line for the carrier color signal, which is formed from the three primary color signals and is achromatized as necessary, and the horizontal scanning line for the achromatic control signal are different by the above-mentioned delay, e.g. , when capturing an image of a subject with a band-shaped high-brightness area BR as shown in FIG. This results in a composite video signal lacking achromatic processing.

In order to avoid such a situation, it may be possible to form an achromatic control signal from a carrier color signal that has undergone vertical correlation calculation, but if this is done, the above-mentioned patent application No. 61-302
Compared to the case where an achromatic control signal is formed based on color signal components as described in Mei. No. 34, appropriate achromatic control may not be performed.

The present invention has been made in consideration of the above points, and proposes a video camera that can appropriately perform achromatic processing on color signals (carrier color signals, color difference signals, or primary color signals) obtained through vertical correlation calculation. This is what I am trying to do.

Means for Solving Problem E To solve this problem, the present invention uses a plurality of delay elements 14 to 17 that delay the imaging signals of a plurality of horizontal scanning lines at the same time vertically by one horizontal scanning period. In a video camera in which the three primary color signals R-B are supplied to the correlation calculation means 13 and the three primary color signals R-B are obtained by the vertical correlation calculation, an image obtained for a horizontal scanning line of the three primary color signals R-B output from the vertical correlation calculation means 13. Based on the color signal components CIX and C2X of the signal PU, the control signal CON for the gain control circuit 22 which performs an achromatic operation by varying the gain is formed.

The three primary color signals R output from the vertical correlation calculation means 13 as color signal components CIX and C2X forming the F action control signal CON.
-Apply the horizontal scan line of G. In this way, the color signal whose gain is controlled in the gain control circuit 22 (in the illustrated embodiment, the carrier color signal) and the control '4! It is synchronized with the I signal CON.

As a result, the output composite video signal COMP
It is possible to avoid the occurrence of horizontal scanning lines with insufficient or excessive achromatization.

Embodiment G An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, for example, a CCD (charge co
The imager 1 has a checkerboard coating of color filters, which is often used when the number of pixels is small, as shown in FIG. Light, light/
After being electrically converted, it is sequentially read out from each imaging cell and output as an imaging signal PU. This imaging output pu is A
GC (automatic gain control.

l) After level adjustment via the circuit 2, the signal is applied to the color 4g signal processing circuit 10 and the luminance signal processing circuit 30.

In the color signal processing circuit 10, two sample and hold circuits 11 and 12 are used to process the 2 samples contained in the image signal PU.
2 color signal components (in the case of the coating in Figure 3, 2 color signal components)
separate the two primary color signals).

That is, as shown in FIG. 3, each horizontal scanning line...
...L (N-1), LN, 'L (N+1)...
As for ..., since the imaging cells coated with the color filters of the two color signal components are arranged alternately, the sampling timing for the sample and hold circuits 11 and 12 is set by the time corresponding to the interval between the imaging cells. By shifting, each sample-and-hold circuit 11 and 12 separates and outputs two color signal components C1 and C2.

These separated color signals C1 (C1(X+1)) and C2
(C2(X+1)) is directly given to the matrix circuit 13 for vertical correlation calculation, and is also given to the matrix circuit 13 after being delayed by one horizontal scanning period (IH) via IH delay lines 14 and 15. The delayed color signals CIX and C2X are delayed by IH via IH delay lines 16 and 17 and are applied to the matrix circuit 13 (
Note that X=1.2..., N...).

In this way, the matrix circuit 13 is provided with color signals C1(X-1) to C2(X+1) regarding the imaging cells for the same three consecutive horizontal scanning lines in the vertical direction. The matrix circuit 13 receives the incoming color signal C1 (X-
1> and C2(X-1), CIX and C2X, C1(X
+1) and C2(X+1), arithmetic processing such as vertical correlation calculation is performed to obtain primary color signals R, G, and B of red, green, and blue, which are sent to the white balance circuit 18.

As described above, since only image cells corresponding to two primary color signals are arranged for each horizontal scanning line, information regarding one primary color signal is insufficient. Therefore, the missing primary color signal is formed by performing vertical correlation processing using the primary color signals of the lines L(X-1) and L(X+1) above and below the line LX.

For example, regarding line LN in FIG.
The missing blue signal B is obtained by calculation from the blue signals B of -1) and L(N+1).

The three primary color signals R, G, and B obtained in this manner are subjected to white balance adjustment in a white balance circuit 18, gamma correction in a gamma correction circuit 19, and then provided to a matrix circuit 20 for color difference signal calculation. , are subjected to matrix processing and converted into color difference signals R-Y and B-Y. These color difference signals R-Y and B-Y are given to a modulation circuit 21, subjected to quadrature two-phase modulation, converted into a carrier color signal CAR, and then passed through a gain control circuit 22 to an addition circuit 4.
given to 0.

On the other hand, in the luminance signal processing circuit 30, the image pickup signal PU
is gamma-corrected in the gamma correction circuit 31, and the correction signal is delayed by H via the IH delay line 32 to be synchronized with the carrier color signal CAR output from the color signal processing circuit 10. Then, the amplification circuit 33 The signal is amplified and provided to the adder circuit 40. In this way, the adder circuit 40 outputs a composite video signal COMP in which the carrier color signal CAR is superimposed on the luminance signal Y.

In addition to the above configuration, the color signal processing circuit 10 of this embodiment
has an achromatic circuit 25. LH delay lines 14 and 1
The color signals outputted from CIX (FIG. 2 (A)) and C2X (FIG. 2 (B)) are given to the maximum value selection circuit 26 of the achromatic circuit 25, and the larger color signal level is selected. and is applied to the slice circuit 27. Slice circuit 2
7 slices the maximum value selection signal MAX (Fig. 2 (C)) at a predetermined slice level SL (Fig. 2 (C)) and gains the output signal C.)N (Fig. 2 (D)). The gain control circuit 22 is given as a gain control signal (achromatic control signal) to the control circuit 22.
The gain is varied according to the gain control signal CON. The gain control (Lt) circuit 22 is configured to reduce the gain as the level of the gain control signal CON increases, and to reduce the level of the carrier color signal CAR, that is, performs achromatic processing.

Therefore, this achromatic circuit 25 performs achromatic processing when provided with color signal components CIX and C2X of a level equal to or higher than the slice level SL.

In the above configuration, when a subject image is given to the imager 1, it undergoes optical/electrical conversion in the imager 1 and is output as an image signal PU.The color signal processing circuit 10 generates a carrier color signal CAR from this image signal PU. Form and add circuit 4
On the other hand, the luminance signal processing circuit 30 performs gamma correction on the luminance signal, synchronizes it with the carrier signal CAR, and supplies it to the addition circuit 40. Thus, the composite video signal COMP is output from the adder circuit 40.

At this time, in the achromatic circuit 25, as shown in FIG.
The maximum value of the color signal components CIX and C2X delayed by IH shown in (B) is selected, and the selected output MAX
(FIG. 2(C)) is sliced at a slice level SL to form an achromatization control signal C0N (FIG. 2(D)), which is supplied to the gain control circuit 22. Thus, the gain control circuit 22 controls the incoming carrier color signal CAR.
Achromatic operation is performed by varying the gain for the image.

Therefore, according to the embodiment described above, since the control signal CON is formed from the color signal components C1x and C2X delayed by IH, the gain control circuit 22
The carrier color signal CAR and control signal CON given to
It is possible to effectively avoid a situation in which there is too much achromatization or not enough achromatization due to the synchronization of the two colors. (At first,
This embodiment can be easily implemented using an existing IC by only making a small configuration change to the IC for vertical correlation calculation so that output signals can be taken out from the IH delay lines 14 and 15.

Incidentally, the synchronization between the carrier color signal and the gain control signal is achieved by the color signal component C from the sample and hold circuits 11 and 12.
1(X-1), C2(X-1) to the achromatic circuit 25 and inserting an IH delay line at the next stage of the modulation circuit 21, but the configuration of the embodiment Compared to this, one extra IH delay line is required, and
The drawbacks described in the specification of Japanese Patent Application No. 61-30234 also remain,
This is still insufficient for practical purposes. It is also conceivable to form the achromatic control signal CON based on the primary color signals R, G, and B output from the matrix circuit 13 to solve the problem of asynchronization with the carrier color signal. −
Since B is obtained by calculation, the color signal component CI
Compared to X and C2X, there is an error in the information regarding the high-luminance portion, and there is a possibility that achromatic control cannot be performed appropriately.

In the above-described embodiment, the present invention is applied to a video camera having a CCD imager 1 in which color filters of three primary colors R-B are checkered coated, but complementary colors (for example, magenta, cyan, yellow etc.) can be used as needed in a video camera equipped with a CCD imager having a checkered coating of color filters. In short, the present invention can be widely applied to video cameras that employ coating methods that require vertical correlation calculations.

Further, in the above embodiment, the three primary color signals R to G are obtained by performing vertical correlation calculations on the video signals of one line each for the upper and lower lines, but the present invention is not limited to this, and other vertical correlation calculations can be performed. It can be applied to the adopted video camera, and in short,
The gain control signal CON may be formed using color signal components synchronized by delay processing with respect to the three primary color signals RG obtained by the vertical correlation calculation.

Further, in the above embodiment, the carrier color signal is controlled by the gain control circuit 22 to perform the achromatic operation, but the present invention is not limited to this, and the primary color signals R to B from the matrix circuit 13 are controlled by the gain control circuit 22. The achromatic operation may be performed by controlling the gain control circuit, or the achromatic operation may be performed by controlling the color difference signals R-Y and B-Y by the gain control circuit.

H Effects of the Invention As described above, according to the present invention, the achromatization operation is performed by synchronizing the color signal to be controlled for achromatization and the control signal for achromatization control, so that excessive achromatization and achromatization can be avoided. It is possible to easily obtain a video camera that can perform appropriate achromatization without causing a shortage situation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a video camera according to the present invention, FIG. 2 is a signal waveform diagram of each part thereof, FIG. 3 is a route diagram showing an example of coating a hot water side cell with a color filter, and FIG. The figure is a route map for explaining the problems of the conventional device. 1... Imager, 10... Color signal processing circuit, lL12... Sample hold circuit,
13... Vertical correlation calculation matrix circuit, 14
~17...IH delay line, 20...
Matrix circuit for color difference signal calculation, 21... Modulation circuit, 22. Old... Gain control circuit, 25...
...Achromatic circuit, 30...Volatility signal processing circuit, 40...Addition circuit.

Claims (1)

[Scope of Claims] Imaging signals of a plurality of horizontal scanning lines are simultaneously applied to a vertical correlation calculation means using a plurality of delay elements that delay by one horizontal scanning period, and three primary color signals are obtained by vertical correlation calculation. control for a gain control circuit that performs an achromatic operation by varying the gain based on the color signal components of the imaging signal obtained for the horizontal scanning line of the three primary color signals output from the vertical correlation calculation means. A video camera characterized by forming a signal.