JPH0824373B2 - Video camera equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera device for home use, surveillance use, industrial use and the like.

2. Description of the Related Art Conventionally, this type of video camera device has a function of automatically performing white balance correction.
Alternatively, the signals of the respective colors are controlled to be equal based on the color signals from the color sensor. FIG. 3 shows the configuration of a white balance correction circuit in a conventional video camera device. In FIG. 3, the output signal of the image pickup device 31 is applied to the signal processing circuit 32, where the R, G, B color signals are separated, and the separated color signals are input to the R, B gain control circuit 33.

The output of the R, B gain control circuit 33 is input to the signal processing circuit 38 as a color signal in a part of the video signal, and another part is a peak hold circuit 34 including an integrating circuit as a color signal for white balance correction. Entered in. The output of the peak hold circuit 34 is a DC signal for each vertical period,
Input to the comparator 35. This comparator 35
From the green signal (hereinafter abbreviated as G) to the red signal (hereinafter R)
Abbreviated) and the blue signal (abbreviated as B below) output is output, and if it is small, it is not output.
This output is rectified by an integrating circuit 36 having a large time constant, and a signal for controlling the magnitudes of R and B (hereinafter
(Abbreviated as R and B control signals).

The slicer 37 determines the upper limit and the lower limit of each control signal, whereby the R, B gain control circuit 33 is controlled so that R = G = B.

In addition, although there are many examples of using a microcomputer for this control,
In that case, the integration circuit 36 and the slicer 37 are merely replaced by a microcomputer, and the basic operation does not change.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional video camera device, since the control is simply to equalize the signals of the respective colors, it is assumed that the information of the color signals is always white. Therefore, even if the information of the color signal is not white, the operation may be performed and the color may be unnatural.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent video camera device capable of controlling by determining whether or not the information of the color signal is white. Is.

Means for Solving the Problems In order to achieve the above object, the present invention provides a video camera device with calculating means for obtaining a color temperature from a ratio of R and B signals, and whiteness as a product of R and B signals. The color signal is controlled and corrected by a calculation means for digitizing by the square root of or the sum of the R signal and the B signal and a judgment function for judging whether the numerical value calculated by these calculation means is within a certain range. It is intended to improve accuracy.

Action The present invention has the following actions by adding the above functions.

That is, as a result of calculating the color signal, if it is confirmed that it is on the distribution of the color temperature change, it is judged as white and the white balance is corrected, but if it is deviated from the distribution of the color temperature change by a certain amount or more, It is judged not to be white, and the white signal is not corrected simply by the color signal.

Therefore, it follows changes in color temperature, but does not follow changes in other colors.

Embodiment FIG. 1 shows the structure of an embodiment of the present invention.

In FIG. 1, the signal extracted from the image pickup device 1 is separated into R, G, and B color signals in a signal processing circuit 2 and input to an R, B gain control circuit 3.

The output of the R, B gain control circuit 3 is partly input to the signal processing circuit 11 as a color signal in the video signal, and another part is input to the peak hold circuit 4 as a color signal for white balance correction. It

The output of the peak hold circuit 4 is input to the A / D converter 5 as a DC signal for each vertical period, and the digitized signal is input to the microcomputer 6. An example of the operation of the microcomputer 6 is shown in FIG.

The R / B control signal output from the microcomputer 6 is converted into an analog signal by the D / A converter 10, and is input to the R / B gain control circuit 3 as in the conventional case to control the color signals (R, B). To do. In this case, the determination means 8 of the microcomputer 6 does not necessarily make R
The control does not work so that = G = B.

Next, regarding the operation of the microcomputer 6,
A description will be given based on FIG. 2 and FIG.

When the apparatus is activated, the R and B control signals of a predetermined level are output in step S2, and the same signal continues to be output until it is changed thereafter. When the color signal is input in step S3, the whiteness and color temperature are calculated by the calculation means 4 for calculating the color temperature / whiteness in step S4.

The whiteness is calculated by the geometric mean of R and B, that is, the square root of R × B when the inputs are R, G, and B, but when the ratio of R and B is small, the average of R and B, that is, (R +
Even B) / 2 is small in error, so this may be simply used. To simply define the whiteness range, R × B or R + B may be calculated without averaging. Further, the ratio of R and B is calculated in order to specify the upper limit and the lower limit of the color temperature.

In step S5, if the result of step S4 is out of the fixed range, the technique is divided into 21, and the R and B control outputs are not changed and the process returns to the color signal input of step S3. If it is within the range, proceed to 22 and go to step S6. This step S5 is the calculation result judging means 8.

In step S6, the R and B control signals are respectively increased or decreased to control R = G = B,
The output is changed in step S7 and passed through the D / A converter 10.
Controls the R and B gain control circuit 3. The steps S6 and S7 are the output control means 9.

In the second and subsequent inputs, the color signal changes in the R, B gain control circuit 3 according to the R, B control signal, so at step S8, the deviation from the initial setting of the R, B control output is calculated at the time of the next calculation ( The correction amount in step 4) is calculated. This step S8 is included in the color temperature / whiteness calculating means 7.

When step S8 ends, the process returns to the color signal input of step S3, and steps S3 to S8 are repeated to continue controlling the white balance.

As described above, according to the above-described embodiment, in the case of a color signal that is not whitish, that is, a color signal that largely deviates from the distribution of color temperature changes, it is possible to avoid unnatural coloring by stopping the white balance correction.

It should be noted that in the above-described embodiment, the calculation result of the color signal has two alternatives, that is, a certain range and a certain range, but this range may be divided into some. For example, it is possible to select one of the three options and to make some correction in the case of an intermediate value. If it is judged to be out of the range, the correction is stopped,
This does not stop, but the circuit can be switched so that a whitish signal is obtained by some method. For example, it is possible to switch the peak hold circuit 4 to an integrating circuit. For these, an optimal method may be used depending on the conditions under which the video camera is used.

EFFECTS OF THE INVENTION As is apparent from the above embodiment, the present invention determines whether or not a color signal is suitable for correcting white balance from the ratio of the R signal and the B signal for the color temperature, and further determines the whiteness as the R signal. The square root of the product of the B signal or the sum of the R signal and the B signal is converted into a numerical value, and it is determined whether these calculated numerical values are within a certain range. Further, since an erroneous operation caused by using an unsuitable signal is avoided, there is an effect that a highly accurate white balance correction can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a video camera device according to an embodiment of the present invention, FIG. 2 is a flowchart diagram of a microcomputer operation of the device of FIG. 1, and FIG. 3 is a block diagram of a conventional video camera device. 1,31 …… Image sensor, 2,32 …… Signal processing circuit, 3,33 …… RB
Gain control circuit, 4, 34 ... Peak hold circuit, 5 ... A / D converter, 6 ... Microcomputer,
7 ... Color temperature / whiteness calculation means, 8 ... Calculation result judgment means, 9 ... Output control means.

Claims (1)

[Claims] 1. A first calculation means for obtaining a color temperature from a ratio between an R signal and a B signal, and a whiteness is quantified by a square root of a product of the R signal and the B signal or a sum of the R signal and the B signal. Second
And a determining means for determining whether the numerical values calculated by these calculating means are within a certain range, and an output means for controlling a color signal by this determining means, and a constant color temperature change. Within the distribution range of
A video camera device characterized by performing white balance correction.