JPH03154590A - Camera - Google Patents

Abstract

PURPOSE:To obtain a proper coloring in actual pickup by using a result of calculation of a standard color balance adjustment value stored in a storage means at pickup and a correction value as a color balance adjustment value so as to use a stable standard light source at the adjustment of a color balance adjustment circuit. CONSTITUTION:Standard color balance adjustment values set to color balance adjustment means 31-33 adjusted so as to output a color signal representing an object image with a proper color balance when the object is lighted by a standard light source are stored and a deviation in the standard color balance adjustment value based on a difference between a color temperature of a light source suitable for the pickup and a color temperature of the color balance adjustment are stored in a RAM 42 as correction values. Then a control means 10 at pickup gives the result of calculation between the standard color balance adjustment value and the correction value to the color balance adjustment means 31-33 as the color balance adjustment value at the pickup. Then a stable standard light source is used at the adjustment of the color balance adjustment means 31-33, then stable adjustment is attained and color balance suitable for the light source is attained in the actual pickup.

Description

[Detailed Description of the Invention] Summary of the Invention In a camera equipped with a circuit for adjusting the color balance of color signals representing a subject image output from a solid-state electronic imaging device, the subject is illuminated with a standard light source for camera adjustment, and an appropriate light source is used to illuminate the subject. The adjustment value given to the color balance adjustment circuit when the color balance adjustment circuit is adjusted so as to obtain a color signal with color balance is stored in a memory as a standard adjustment value. Further, a correction value based on the difference between a color temperature suitable for photographing (for example, 5500K) and the color temperature of the standard light source is stored in the memory. During actual photographing, the result of addition (or subtraction) of the above-mentioned standard adjustment value and correction value is given to the balance adjustment circuit to perform two-color balance adjustment.

BACKGROUND OF THE INVENTION The present invention provides a camera equipped with a solid-state electronic imaging device that outputs a color signal representing a captured image of a subject, and a color balance adjustment circuit that adjusts the color balance of the color signal output from the solid-state electronic imaging device. Regarding.

If this type of camera has a two-color sensor, it is possible to adjust the color balance based on the output signal from the color sensor. However, in order to make the camera as small as possible, the color sensor may be omitted. In this case, the color balance adjustment value of the color balance adjustment circuit (the gain of the amplifier in the color balance adjustment circuit) needs to be fixedly set to a constant value. Therefore, it is necessary to adjust the color balance adjustment value of the one-color balance adjustment circuit.

This adjustment work is preferably performed using a stable standard light source. However, the color temperature of the standard light source does not match the light source (sunlight, strobe light, etc.) used by the camera when shooting, so
If a color balance adjustment circuit that performs color balance adjustment using a standard light source is used as is, there is a possibility that the color balance of the actually photographed subject image will be slightly distorted.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera that can use a stable standard light source when adjusting a two-color balance adjustment circuit, and can also obtain a subject image with appropriate hue during actual shooting. .

The present invention provides a camera equipped with a solid-state electronic imaging device that outputs a color signal representing a captured object image, and a color balance adjustment means that adjusts the color balance of the color signal output from the solid-state electronic imaging device. a first storage means for storing a standard color balance adjustment value set in the color balance adjustment means, which is adjusted so that a color signal representing a subject image having an appropriate color balance is output when the subject is illuminated with the light; a second storage means for storing, as a correction value, a deviation in the color balance adjustment value based on the difference between the color temperature of a light source suitable for photography and the color temperature of the standard light source; The present invention is characterized by comprising a control means for supplying the calculation result of the standard color balance adjustment value and the correction value stored in the second storage means to the color balance adjustment means as a color balance adjustment value.

According to this invention, since a stable standard light source can be used when adjusting the color balance adjustment means of the camera, stable adjustment is possible. Then, during actual shooting, by correcting the standard color balance adjustment value set using the standard light source using the correction value, a color balance suitable for the light source in the actual shooting is achieved, so you can capture the appropriate subject with 9 shades. A video signal representing the image can be obtained.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a still video camera (electronic still camera) will be described in detail.

FIG. 1 shows part of the electrical configuration of a still video camera.

The overall operation of the still video camera is controlled by the control unit IO.
supervised by. This control device 10 is composed of a CPU, memory, interface, etc.

The imaging optical system 20 includes an imaging lens system 21. for forming a subject image. It consists of an aperture 22 and a shutter (as shown; the shutter can also be implemented as an electronic shutter). Also, a photometric element 23 for measuring the illuminance of incident light.
is arranged, and a signal representing the constant illuminance of the aFI is input to the control device IO.

The aperture 22 is controlled by a control device IO.

A solid-state imaging device 24 such as a COD is arranged on the focal plane of the optical system 20, and this device outputs color signals of three primary colors, R (red), G (green), and B (blue) representing the subject image. do. In the electronic shutter system, the signal charge accumulation time of the solid-state imaging device 24 is controlled by the control device 10. The video data of the subject imaged on the imaging device 24 is read out as three-color video signals in synchronization with a synchronization signal given by the control device 10, and is sent to the preamplifier circuits 25, 28, 27, . First variable gain amplifier circuit (color balance adjustment circuit of solid-state imaging device 24 itself) 28.29.30. The signal is input to the process matrix circuit 34 through a second variable gain amplifier circuit (color balance adjustment circuit) 31, 32, and 33, respectively.

1st. Among the second variable gain amplifier circuits 28 to 33, a control signal from the electronic volume circuit 45 is applied to the variable gain amplifier circuit 28.31 to which the color signal R is input and the variable gain amplifier circuit 30.33 to which the color signal B is input. The gain of each signal is adjusted based on this control signal.

A luminance signal Y and two color difference signals R-Y and B-Y are created in a process matrix circuit 34, and these signals are then input to a recording signal processing circuit 35. This processing circuit 3
5 includes a line sequential circuit, a pre-emphasis circuit, an FM modulation circuit 1 synthesis circuit, etc., and an FM-modulated synthesized video signal is output from this circuit 35 and sent to a gate circuit 3B for recording control.

Still/video magnetic disk 11 is driven by disk motor 3
8 for a fixed rotation speed, e.g. 3600r, p, fll
.

Rotationally driven. A magnetic head 37 for recording is in contact with the magnetic disk 11, and a phase detection pulse PG of 1 @ is applied to the core of the magnetic head 37 for each rotation of the magnetic disk 11.
A phase detector 12, which generates , is nearby. The magnetic head 37 is transported in the radial direction of the magnetic disk 11 by the transport mechanism and positioned on a predetermined track. The phase detection pulse PG is given to the control device 10.

A RAM 42 is connected to the control device 10. This R
AM42 is a nonvolatile RAM. RAM42 in Figure 2
Some of the contents are shown.

Still video cameras have their color balance adjusted in advance using a standard light source. This adjusted color balance is then corrected during actual shooting. Therefore, the standard adjustment value R8 of the color signal R and the standard adjustment value B of the color signal B are stored in the RAM 42. Also, a correction value r for color signal R and a correction value s for color signal B are stored.

Standard adjustment values R6 and B. is for adjusting the variable gain adjustment circuits 31 and 33 so that appropriate color balance adjustment is performed at the color temperature of the standard light source for camera adjustment.

This is set as follows. The subject is illuminated by a standard light source. The adjustment mode is selected by mode switch MO. Images captured under standard light source illumination are displayed on a monitor or television. In order to adjust the color signal R, the gain of the amplifier circuit 31 (standard! 1! adjustment value R8
), the select switch 53 selects the R signal. The switch 50 is for up/switching and the switch 51 is for down/swiping.

By operating these, the standard adjustment value R8 is adjusted. When a light command is input from the switch 52 when the red color of the image on the monitor/television has an appropriate hue, the final standard adjustment value R8 is written into the RAM 42.

The standard adjustment value Bo of the color signal B can also be set by the same operation after selecting the color signal B with the select switch 53.

The correction values r and b give the deviation of the adjustment value based on the difference between the color temperature of the standard light source and the color temperature (for example, 5500K) of a light source suitable for actual photography (sunlight, strobe light, etc.). Figure 3 shows color temperature and control voltage (amplifier circuit a).
i, the gain is determined by the voltage applied to sa). As can be seen from this figure, the difference in control voltages based on the difference between the color temperature of the standard light source and the color temperature at the time of photographing is the correction value r, b.

This correction value is obtained by selecting the correction value input mode with the mode switch 41, selecting r or b with the select switch 53, and changing the value with the up switch 50 and down switch 51 until the appropriate value is set. By inputting a write command from the switch 52 when the
It can be written to RAM 42. These switches 4
0.41. It goes without saying that 50 to 53 can be used in combination as appropriate.

A liquid crystal panel 43 is also connected to the control device 10 and visually displays various information for the adjustment operator and photographer.

When actual photographing is performed, corrected color balance adjustment is performed. That is, the adjustment standard values R, Bo and correction values r, b are read out from the RAM 42. Each read data is given to the control device 1o. In the control device 10, the adjustment standard value R8 and the correction value r are added as data for controlling the gain of the color signal R, and the variable gain amplifier circuit 3
1 control data R-(Ra + r) is calculated.

This data is then given to the electronic volume circuit 45.

The electronic volume circuit 45 includes a D/A conversion circuit and outputs a voltage signal (control voltage) according to the input data R1. A voltage signal output from the electronic volume circuit 45 is used for gain control of the variable gain amplifier circuit 31.

The same applies to the gain control of the variable gain amplifier circuit 33 for the color signal B. That is, the control device 10 adjusts the standard value B. and the correction value S are added, and the variable gain amplifier circuit 33
The control data B - (Bo+b)■ is calculated. Then, the gain of the variable gain amplifier circuit 33 is controlled based on this signal.

The gains of variable gain amplifier circuits 28 and 30 are also adjusted to predetermined values by the output voltage of electronic volume circuit 45.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the invention. FIG. 2 shows an example of the contents stored in the RAM. FIG. 3 is a graph showing the relationship between color temperature and control voltage. 1 (1... Control device. 28-33... Variable gain amplifier circuit. 42... RAM. That's all.

Claims (1)

[Scope of Claims] A camera equipped with a solid-state electronic imaging device that outputs a color signal representing a captured image of a subject, and a color balance adjustment means that adjusts the color balance of the color signal output from the solid-state electronic imaging device. , a first color balance adjustment value that stores a standard color balance adjustment value set in the color balance adjustment means, which is adjusted so that a color signal representing a subject image with appropriate color balance is output when the subject is illuminated with a standard light source; a storage means, a second storage means for storing, as a correction value, a deviation in the color balance adjustment value based on the difference between the color temperature of a light source suitable for photographing and the color temperature of the standard light source; and the first storage means at the time of photographing. A camera comprising: control means for providing a calculation result of the standard color balance adjustment value stored in the storage means and the correction value stored in the second storage means to the color balance adjustment means as a color balance adjustment value.