JPS6361589A - Still video camera - Google Patents

Abstract

PURPOSE:To realize a color tone comparatively close to the real color even if a color sensor is erring by controlling a color balance adjusting circuit by means of a prescribed constant color temperature in case the measured illuminance is below a prescribed value. CONSTITUTION:If a release button 30 is further depressed to reach the second phase, the measured illuminance resulted by a photometry element 33 is read. In case the illuminance is below 150Lx, the color balance adjustment based on the color temperature of 3,200K is executed. In case the measured illuminance exceeds 150Lx, the output of the color temperature sensor 40 is read by a controller 10. And based on thus read color temperature, the gains of amplifier circuits 11-13 are adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention A color temperature detection sensor for color balance adjustment will produce an error if there is not a certain amount of incident light. Therefore, when shooting still video in a relatively dark environment, that is, when the illuminance detected by the photometric element placed in the imaging optical system is below a predetermined value, the color temperature for one color balance adjustment must be set to a predetermined value. Fixed value, for example tungsten light (indoor light).

BACKGROUND OF THE INVENTION The present invention relates to a still video camera (electronic still camera) that photographs a subject with an electronic imaging device and records the still video signal on a magnetic disk.

Since still video cameras handle color video signals, color balance and adjustment of the color signals is necessary. Conventional still video cameras are equipped with a color temperature sensor that measures the color temperature of illumination light including sunlight, and color balance adjustment is performed based on the color temperature detected by this sensor.

However, a single color temperature sensor does not work accurately unless there is a certain amount of light of 17 degrees. When shooting in a relatively dark environment, such as when shooting under miniature light bulbs or night scenes, the color temperature detected by the color temperature sensor may contain errors, so color balance adjustment is performed based on this detected color temperature. This results in the recording of a color video signal whose color tone does not actually match.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video still camera that can perform color photographing and recording in accordance with actual conditions even in a relatively dark environment.

The still video camera according to the present invention includes: 7 photometric elements for detecting the illuminance of human light; 1 color balance adjustment circuit for color signals;
The apparatus includes means for determining whether the illuminance measured by the photometric element is below a predetermined value, and means for controlling the color balance adjustment circuit according to a predetermined constant color temperature when the measured illuminance is below the predetermined value. It is characterized by

The above predetermined value of illuminance is 150Lx in the example described below.
However, it can be arbitrarily determined depending on the sensitivity of the color temperature sensor and other factors. 71111 An example of the color temperature to be fixed when the constant illuminance is below this predetermined value is the color temperature of 3200K of tungsten light (natural light bulb), but it is also possible to adopt a color temperature of other pressure. .

According to this invention, when shooting still video in a relatively dark environment, the color for color balance adjustment as described in 1, 1- is fixed at a certain value of n degrees. This means that even if the color sensor has an error, it is possible to record a color video signal that represents a color tone that is relatively close to the actual color. Even if this is played back, it will still hold up well to appreciation.

Needless to say, if the A11l constant illuminance exceeds the predetermined value, the color palette 1-1 adjustment is performed based on the detected color 72i degrees of the color temperature detection sensor.

DESCRIPTION OF THE EMBODIMENTS 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 device 10.
supervised by. This control device 1° includes a CPU,
It consists of 14 components including memory, interfaces, etc.

The imaging optical system 36 includes an imaging lens system 31. for forming a subject image. It is composed of an aperture 32 and a shutter 34. A photometric element 33 for iDJ determining the illuminance of the incident light is arranged in a part of the optical path of the optical system 36, and a signal representing the measured illuminance is manually inputted to the control device 10. The aperture 32 and shutter 34 are controlled by the control device 10 as described later.

A solid-state imaging device 35 such as a CCD is disposed on the focal plane of the optical system 36, and this device has three primary colors, R
It has imaging surfaces for (red), G (green), and B (total). The video data of the subject imaged on the imaging device 35 is read out as three-color video signals in synchronization with a synchronization signal given by the control device 10, and is read out as a three-color video signal by a preamplifier circuit (not shown), a variable gain amplifier circuit ( The color balance adjustment circuit) 11, 12, and 13 are manually inputted to the process matrix circuit 14, respectively. This circuit 14 produces a luminance signal Y and two color signals R-Y and B-Y, and these signals are then input to a recording signal processing circuit 15. This processing circuit 15 includes a line sequential circuit, a pre-emphasis circuit, an F
An FM-modulated composite video signal is outputted from this circuit 15 and sent to a gate circuit 17 for recording control.

Still/video magnetic disk 21 is driven by disk motor 2
3 at a constant rotational speed, for example, 360 degrees r, p, m. A magnetic head 22 for recording is in contact with this magnetic disk 21, and a position detector 25 that generates one phase detection pulse PG for each rotation of the magnetic disk 21 is adjacent to the core thereof. are doing. The magnetic nodal 22 is transferred in the radial direction of the magnetic disk 21 by the transfer mechanism and positioned on a predetermined track. The phase detection pulse PG is given to the control device 10.

The Nyatta release button 30 is of a two-step stroke type, in which the first step of pressing releases the switch S1, and the second step of further pressing the button 30 releases the switch S2.
or each will be turned on.

A color temperature detection sensor 40 is provided to measure the color temperature of illumination light in order to adjust the color balance of the video signal. As is well known, this sensor 40 includes a light receiving element 43.44 that receives light incident through R and B filters 41.42.

A logarithmic (log) amplification circuit 45 that amplifies these outputs.
j, l, j,
The output of the differential amplifier circuit 47 is converted into a digital quantity by the A/D conversion circuit 48 and inputted to the control device 10.

Although not shown, this camera is equipped with a main power source and an auxiliary power source. The control device 10 is in a standby state by the auxiliary power source except when shooting.

As will be described later, when photographing begins, the main molds Fi and ρ are turned on.

The procedure of color balance adjustment processing by the control device 10 during photographing operation is shown in FIG.

When the control button 30 is pressed the first stroke, the switch S1 is turned on. Then, the main power is turned on to various circuits including the motor 23, and the motor 23 is started.

When the release button 30 is further pressed to reach the second stage, the switch S2 is turned on. Then, the photometric element 33
The measured illuminance is read (step 51). The aperture value and shutter speed are determined based on this measured illuminance, and the aperture 32 is controlled to achieve the determined aperture value.

Further, it is determined whether the read measured illuminance is 150Lx or less (step 52). If the measured illuminance is 150Lx or less, color balance adjustment is performed based on the color temperature of 3200 (step 55). That is, in the control circuit 10, the amplifier circuit 1
Gains of 1 to 13 are determined, and command signals are given to the amplifier circuits 11 to 13 so as to obtain the gains.

, 11. If the constant illuminance exceeds 150Lx.

The output of the color temperature sensor 40 is read into the control device 10 (step 53), and the gains of the amplifier circuits 11 to 13 are adjusted based on the read color temperature (step 54).

After this, a shirt open signal is output from the control device 10. This causes the shutter 34 to open for a certain period of time. Further, a gate open signal is applied to the gate circuit 17 for a period of one cycle of the phase detection pulse. The imaged and processed video signal is applied to the magnetic head 22 through the gate circuit 17. A video signal for one still image is recorded on the magnetic disk 21 on a predetermined track while the magnetic disk 21 rotates once.

When this sequence is completed, the main power is turned off and the motor 23 is stopped.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a part of the electrical configuration of a still video camera, and FIG. 2 is a flowchart showing a color balance adjustment processing procedure forming a part of the photographing processing procedure. 10...Control device. 11, 12.13...Variable gain amplifier circuit (color distortion-free one-week adjustment circuit). 33...∆+IJ photoreceptor, 40... Color temperature detection sensor. Applicant: Fuji Photo Film Co., Ltd. Agent: Asamichi Kato (one other person)

Claims (2)

[Claims] (1) A photometric element that detects the illuminance of incident light, a color balance adjustment circuit for color signals, a means for determining whether the illuminance measured by the photometric element is below a predetermined value, and a means for determining whether the illuminance measured by the photometric element is below a predetermined value. A still video camera comprising: means for controlling the color balance adjustment circuit according to a predetermined constant color temperature. (2) A patent further comprising: a color temperature detection sensor; and means for controlling the color balance adjustment circuit based on the color temperature detected by the color temperature detection sensor when the measured illuminance exceeds the predetermined value. A still video camera according to claim (1).