JPH0285834A - Electronic still camera system - Google Patents

Abstract

PURPOSE:To offer a camera system for executing an appropriate color adjustment in accordance with each separate stroboscopic device by providing the stroboscopic device for holding color temperature information peculiar to an electronic flash light emission, reading in the color temperature information at the time of using the stroboscope and adjusting a white balance of a video signal. CONSTITUTION:In a system which can use plural kinds of stroboscopic device, this electronic still camera system can execute an appropriate color adjustment in accordance with each separate stroboscopic device. A stroboscopic device 10 holds color temperature information peculiar to an electronic flash light emission, and its color temperature information is read in a color temperature reading-in circuit 62 in a control circuit 48 from an output circuit 60 in the stroboscopic device 10. At the time of using the stroboscope, white balance of a photographed video signal is adjusted in accordance with the read-in color temperature information, therefore, an appropriate white balance corresponding to a light emission color temperature of each separate stroboscopic device can be obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to electronic still camera systems.

[Conventional technology]

In an electronic still camera system, white balance control during strobe light emission involves setting the white balance to daylight, which corresponds to the color temperature of the strobe device (Japanese Patent Application No. 57-31228).
), a configuration that sets the white balance to daylight color when using a strobe and the outside light is dark, a configuration that determines the white balance based on the guide number, subject distance, photometric value of normal light, and colorimetric value, etc. It has been known.

[Problem to be solved by the invention]

In the conventional example, even if a plurality of types of strobe devices can be installed, white balance control when using a strobe is limited to one method. This is because in the case of strobe photography, the illumination condition of the subject before the photograph is different from the illumination condition of the subject at the time of photographing (the condition in which the strobe light is irradiated). This is because it is not possible to carry out formalities, etc.).

However, if multiple types of strobe devices are available,
Differences in color temperature occur due to the type of strobe device used and differences in characteristics even within the same model, and in the case of dimmable strobe devices, due to differences in the flashing time. Not considered at all.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electronic still camera system that performs appropriate color adjustment according to each individual strobe device in a system that can use a plurality of strobe devices.

[Means to solve the problem]

An electronic still camera system according to the present invention includes a strobe device that retains color temperature information specific to strobe light emission;
The electronic still camera is equipped with a reading means for reading the color temperature information, and when using a strobe, adjusts the white balance of a photographed video signal according to the read color temperature information.

[Effect]

By having the strobe device itself retain color temperature information specific to strobe light emission, and using that information to adjust white balance when using the strobe, it is possible to achieve an appropriate white balance according to the light emission color temperature of each strobe device. You can find balance.

〔Example〕 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention.
0 is equipped with a light receiving element and measures the amount of reflected light from the subject,
This is a so-called dimming type strobe device that stops emitting light when the appropriate exposure amount is reached for the set aperture value and the sensitivity of the image sensor. 12 is a color measurement circuit that measures the color temperature of the light shining on the subject; 14 is a photometry circuit that measures the brightness of the subject; 16 is a photographic optical system; 1 is an aperture; 20 is an aperture 1 to a specified aperture value;
8, an aperture control circuit that controls 22, a shutter device 22;
is an image sensor such as a CCD; 26 is a signal processing circuit that performs sample/hold, color temperature correction, gamma correction, etc. on the output of the image sensor 24; 28 is a modulation circuit that performs FM modulation on the output of the signal processing circuit 26; 30 is a recording amplifier, 32 is a magnetic head, 34 is a still video floppy disk, 36
is a PG coil that detects the rotational phase of the floppy 34, 3
8, in accordance with the rotational phase signal from the PC coil 36, transfers lock and sample/hold pulses to the image sensor 24, clamp pulses, synchronization signals, etc. to the signal processing circuit 26, carriers, etc. to the modulation circuit 28, recording amplifier 30
This is a synchronization signal generation circuit that supplies a recording gate signal to the

40 is a spindle motor that rotates the floppy disk 34;
42 is a control circuit for the motor 40; 44 is a head drive mechanism that moves and loads/unloads the magnetic head 32; 46;
48 is a head control circuit that controls the head drive mechanism, 48 is a control circuit that operates the various parts shown in accordance with external inputs such as photometry and colorimetry, and operations according to the photographer's will; 50 and 52 are linked to a release button (not shown). The switch is arranged so that the first stroke of the release button turns on the switch 50, and the second stroke turns on the switch 52.

Referring to FIG. 2, the operation in normal photographing without using the strobe device 10 will be described first. When the switch 50 is turned on with the first stroke of the release button (Sl
), the power (not shown) is turned on, the control circuit 48 starts the spindle motor 40 by the motor control circuit 42 (S2), and when it detects that the floppy 34 rotates at a predetermined speed (S3), the head control circuit 46 and The head drive mechanism 44 moves the magnetic head 32 to a predetermined track position.
Move it and load it onto the floppy 34 (S4)
. Next, the subject brightness is read from the photometry circuit 12 (S5
), the aperture value and shutter speed are determined according to a predetermined program diagram (S6). Further, the color temperature of the object irradiation light is read from the color embellishing circuit 12 (S7), and the amount of gain correction for the R signal and B signal in the signal processing circuit 26 is determined (S8). Until the switch 52 is turned on, that is, while only the switch 50 is on, the above-described photometry, colorimetry, and determination of the gain correction amount are sequentially performed (S15).

When the switch 52 is turned on (S9), the aperture 16 is controlled according to the values determined in steps 85 to S8 (5IO), and the gains of the R and B signals of the signal processing circuit 26 are controlled (Sll
), the shutter device 222 is driven according to the determined shutter speed, and the image sensor 24 is exposed to light (51
2). The output of the image sensor 24 resulting from this photographing operation is recorded on the floppy disk 34 (S13). At this time, the synchronization signal generation circuit 38 responds to the output (PG pulse) of the PG coil 36 in synchronization with the rotation of the floppy disk 34. The opening timing of the shutter device 22, the transfer timing of the side image element 24, etc. are controlled.

When the recording operation on the floppy disk 34 is completed, the head control circuit 46 and head drive mechanism 44 send the magnetic head 32 to the next vacant track in preparation for the next photographing and recording (S14).

When switch 50 is turned off, head 32 is unloaded, spindle motor 40 is stopped, and power is turned off (516).

3 and 4 show block diagrams of a configuration for transmitting characteristic data of the strobe device 10 to the control circuit 48. In FIG. 3, 60 is an inherent color temperature output circuit in the strobe device 10; is an A/D converter in the control circuit 48 as a strobe color temperature reading circuit. In this way, the color temperature information specific to the strobe device 10 is output as an analog value such as voltage, current, resistance value, frequency, etc., and the control circuit 48 reads it as necessary. The unique color temperature information of IO is stored in the shift register 64, and a shift clock is sent from the clock generation circuit 66 in the control circuit 48 to read it into the shift register 68 in the control circuit 48.

The operation when using the strobe device 10 will be explained. In this case, the processes A and B in FIG. 2 are changed as shown in FIG. 5. That is, (a) in FIG. 5 is process A.
('b) is the part that replaces the process. In FIG. 5(a), the control circuit 48 checks the charging completion signal a from the strobe device 10 (S20), and if charging is completed, sets the strobe flag (S21), and sets the strobe light control aperture value C. is read from the strobe device 10 (S22) and the aperture 18 is set to that value (523).
, reads the unique color temperature information held by the strobe device 10 (S24), determines a gain correction value for white balance of the signal processing circuit 26 according to this and applies it to the signal processing circuit 26 (S25), If strobe charging is not completed (S20), reset the strobe flag (526), read the photometric data f from the photometric circuit 14 (S27), calculate the aperture value and shutter time (528), and reset the flash flag (526). Colorimetric data e from 12
is read (S29), and a gain correction amount for white balance is set (S30).

In the photographing process of Fig. 5 (bl), if the strobe flag is 1 (S32), wait for the shutter 22 to be fully opened (S33.
5) Wait for the time equivalent to the flashing of the strobe device 10 (S3
6), Turn off the X contact (537), close the shutter 22 (338), wait for the shutter 22 to close completely (
S39). If the strobe flag is 0, the shutter 22 is opened for the previously set shutter time (S40.41.42.39).

In the above embodiment, the color temperature specific to the strobe can be corrected, but it is impossible to correct the color temperature based on the light emission time in a flash device such as a dimmable flash whose light emission time changes depending on the shooting conditions. In order to correct the color temperature according to the flash emission time, the color temperature information should not be read from the strobe device 1o in the process A of FIG. The strobe-specific color temperature information with the difference corrected may be read into the control circuit 48, and the white balance may be adjusted accordingly.

FIGS. 6 and 7 are block diagrams showing a configuration for transmitting a color temperature correction value based on light emission time from the strobe device 10 to the control circuit 48. FIG. 6 shows the case of transmitting an analog value, where 70 is a circuit that generates a voltage indicating a color temperature specific to the strobe device 10, 72 is an integrating circuit, and 74 is the output of the voltage generating circuit 70 and the output of the integrating circuit 72. 76 is a switch that is closed when strobe light emission starts and is opened when light emission is stopped. 77 is a switch that is opened when strobe light emission is started. 78 is an A/D converter similar to 62.

By opening and closing the switches 76 and 77, when strobe light emission is stopped, the output of the integrating circuit 72 becomes a voltage proportional to the light emission time. Therefore, the output of the adder 74 is a voltage corresponding to the strobe color temperature information including correction based on the light emission time, and the control circuit 48 reads this voltage with the A/D converter 78. Note that the switch 77 is set at an appropriate timing before the next light emission starts (after the control circuit 48 reads the color temperature information).
Close it with.

FIG. 7 shows an example configured using a digital transmission method. A pulse generating circuit 80 generates pulses at regular intervals, and these pulses are sent to a counter via a switch 81 that turns on when light emission starts and turns off when light emission stops. 82. Address decoder 83 accesses ROM 84 using the count value of counter 82 as an address. The ROM 84 stores a color temperature correction value based on the flash time at an address corresponding to the flash time, and the data read from the ROM 84 is transferred to the shift register 85 after the strobe light stops flashing. 85 transfers data to the shift register 87 in the control circuit 48 in accordance with the transfer lock from the clock generation circuit 86 of the control circuit 48 . This allows the control circuit 48 to know color temperature information specific to the strobe that has been corrected based on the light emission time. The configuration shown in FIG. 7 has the advantage that it can be easily applied even when the change in color temperature with the emission time is not monotonous with respect to the emission time.

In this way, the white balance can be adjusted by taking into account the difference in color temperature due to the light emission time. (The shorter the better, considering the problem of thermal charge generated.) However, there is a problem in that the strobe device 10 side must calculate a correction value for the inherent color temperature based on the light emission time and transfer it to the camera side (control circuit 48). arise. Therefore, as shown in FIG. 5(a), the unique color temperature information of the strobe device 10 is read into the control circuit 48 and temporarily set when setting the surrounding conditions, and after shooting, the correction value based on the light emission time is controlled. Load it into the circuit 48,
The temporarily set white balance correction value may be corrected before the start of exposure. The recording operation on the floppy 34 is performed in synchronization with the PG pulse from the PG coil 36, but since the exposure of the image sensor 24 is performed at any timing according to the user's will, the time from exposure to recording is not constant. Therefore, depending on the timing from exposure of the image sensor 24 to recording on the floppy disk 34, the correction after photographing may be omitted, and in this case, the result will be the same as that shown in FIG.

In the above embodiment, the color temperature data unique to the strobe device 10 itself is transmitted from the strobe device 10 to the control circuit 48, but as an electronic camera system, the color temperature of the strobe device as a reference is set. The deviation from the reference value is measured from the individual strobe device 10 to the camera side (control circuit 4
8). In this way,
The amount of color temperature information transmitted can be reduced, and it is also possible to use a conventional strobe device that does not include a color temperature information output circuit. In this modified example, in step S25 of FIG. 5(a), the control circuit 48 temporarily sets a white balance correction value in accordance with a reference color temperature held in a ROM or the like.

Then, at the time of photographing (specifically, after the strobe light emission has stopped), the deviation value of the color temperature according to the light emission time of the strobe device used is read, and the white balance correction value temporarily set earlier is corrected.

Also, when reading the deviation value, it is possible to set the white balance correction value by calculating it with the reference value, but from the perspective of reducing the release time lag, it is recommended to temporarily set the reference value first. is desirable.

When photographing with the image sensor 24, reading of strobe color temperature information (specific color temperature information, color temperature correction value, light emission time, etc.) and calculation of white balance correction value can be performed using the shutter after the strobe light has been emitted. You may also do this when you are running No. 22. In this way, the time from exposure to recording can be shortened. Furthermore, if the signal format of the color temperature information read into the control circuit 48 from the strobe device 10 is the same format as the color temperature information from the color embellishing circuit 12, processing in the control circuit 48 becomes easier. Furthermore, a multiplexer may be provided on the input side of the reading circuit on the control circuit 48 side, and may also be used for reading the output of the embellishing circuit 12. In this case, the charge completion signal can be used to switch the multiplexer.

In addition, in the embodiment of the dimming type strobe device, the strobe device 10 side calculates the color temperature correction value corresponding to the light emission time, but the strobe device does not provide strobe-specific color temperature information (or standard The deviation value from the value) and the light emission time information itself may be transferred to the control circuit 48, and the control circuit 48 may perform correction calculations based on the light emission time.Furthermore, the light adjustment operation may be performed by the strobe device. Alternatively, it may be performed on the camera side (control circuit 48) side.

A so-called TT that performs a light control operation using the light that has passed through the photographic optical system 16
In the case of L direct AT light, the set aperture value and flashing time are determined on the camera side (control circuit 48), so fewer signals are transmitted from the strobe device to the camera side. For example, when the switch 50 is turned on or the strobe device is attached, the strobe-specific color temperature data (or deviation from the reference value) and correction information for the light emission time need only be transferred to the camera side once. .

In a configuration that assumes a reference strobe device, if a strobe device that does not have a means for transmitting color temperature data unique to the strobe (or color temperature data corrected by light emission time) is installed, as a means for detecting that it does not have a means for transmitting color temperature data (or color temperature data corrected by light emission time). , FIG. 3 and FIG. 6, a pull-up resistor is provided on the input side of the A/D converter 62.78, and from the above sending means of the strobe device, the output corresponds to a full set of A/D converters 62.78. Set it so that no voltage is output. Then, when the voltage corresponding to the full set of the A/D converter 62.78 is read, it can be determined that the input of the A/D converter 62.78 is open, and the strobe device without the above-mentioned sending means can be used. It can be determined that there is. In FIGS. 4 and 7, the input of the shift register 64.85 is pulled up or pulled down, and the shift register 64.85 specifies that all 1" or all "O" data is not output. By doing so, it can be determined whether or not the above-mentioned sending means is provided.

〔Effect of the invention〕

As can be easily understood from the above description, according to the present invention, the accuracy of white balance when using a strobe can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the configuration of an embodiment of the present invention, Fig. 2 is an operation flowchart when the strobe is not used, and Fig. 3 is a block diagram of the configuration of an embodiment of the present invention.
4 and 4 are block diagrams of the configuration for transmitting the unique color temperature information of strobe device 10 to the control circuit 48, FIG. 5 is the main part of the operation flowchart when using the strobe, and FIGS. 6 and 7 are the FIG. 3 is a block diagram of a transmission configuration of color temperature correction information based on light emission time in the case of an optical strobe device.

Claims (1)

[Claims] An electronic still device that is equipped with a strobe device that retains color temperature information unique to strobe light emission and a reading means that reads the color temperature information, and that adjusts the white balance of a photographed video signal according to the read color temperature information when using the strobe. - An electronic still camera system characterized by consisting of a camera.