JPH0620314B2 - Video camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video camera to which a DP adapter for film shooting can be attached.

[Prior art]

When using a video camera at home, as a method of adjusting the color temperature of the light from the subject, a part of the signal photoelectrically converted by an image pickup device such as an image pickup tube or a solid-state image pickup device is used for white balance adjustment. The second method using the setting signal, the light from the subject is detected by the light receiving element to obtain the color temperature, and the gains of the variable gain amplifier for the red signal and the variable gain amplifier for the blue signal are adjusted to achieve white balance. The first method of adjusting is known.

When adjusting the white balance, considering the operability, ease of workability, and color reproducibility for the operator,
It can be said that the first method is superior to the second method.

However, when a DP adapter is attached to a video camera to shoot a film or slide film,
The color temperature detector of the above method is attached to the case of the video camera, and the lamp for the film or slide film lighting installed in the adapter is located behind the film or slide film. Since the light from the above can not be detected by the color temperature detector attached to the case of the video camera, there is an inconvenience that it is difficult to take an image with proper color temperature compensation.

Therefore, conventionally, the white balance adjustment button provided on the case of the video camera is operated to set an appropriate constant value, and the standard state is used for shooting.

A conventional video camera having such a configuration will be described with reference to FIG.

[Explanation of FIG. 1] In FIG. 1, reference numeral 1 denotes an image pickup device such as an image pickup tube or a solid-state image pickup device, which photoelectrically converts light information from a subject incident through a lens 1 and outputs the photoelectrically converted information. It is scanned, taken out, and input to the preamplifier 2. Reference numeral 3 denotes a separation circuit that separates the input video signal into a luminance signal y and a color signal C. The luminance signal y from the separation circuit 3 is input to the process circuit 5, and the color signal from the separation circuit 3 is a color signal. It is input to the separation circuit 4. The process circuit 5 the low-frequency luminance signal y _L separates and extracts from the input luminance signal y, a low-frequency luminance signal y _L is input into the process circuit 6 and 7, the luminance signal y is negative-positive (N / P) inverting circuit 15 is input.

The color separation circuit 4 receives the input color signals C to R
The (red) signal and the B (blue) signal are separated and extracted, and the R signal is input to the process circuit 6 and the B signal is input to the process circuit 7.

Reference numeral 8 is a scattering plate for receiving light incident from the outside at a wide angle, and a filter 9a for detecting red light is behind it.
And a filter 9b for detecting blue light, and a photodiode 10a for photoelectrically converting red light and a photodiode 10b for photoelectrically converting blue light are provided behind the filters 9a and 9b. Reference numerals 11a and 11b denote amplifiers. The amplifier 11a amplifies the R signal photoelectrically converted by the photodiode 10a from the red light incident through the red light detecting filter 9a and inputs the amplified R signal to the logarithmic operation circuit 12a, and the amplifier 11b. Amplifies the B signal obtained by photoelectrically converting the blue light incident through the blue light detecting filter 9b by the photodiode 10b and inputting it to the logarithmic calculation circuit 12b. Reference numeral 12c is a subtracter, which subtracts the R and B signals output from the logarithmic operation circuits 12a and 12b to obtain a color temperature signal, which is inverted by the process circuit 7 and the inverting amplifier 13 and then the process circuit 6 Then, the gains of the process circuits 6 and 7 are changed according to the color temperature signal to adjust the white balance.

The process circuit 6 outputs the color difference signal R-y _L to the process circuit 7
Outputs a color difference signal B-y _L, which is input to the color modulation circuit 14, respectively. The color signal C output from the color modulation circuit 14 is input to the negative / positive (N / P) inversion unit 15,
The encoder 16 in the next stage converts the color signal into an NTSC color signal and outputs it from the output terminal 26.

Reference numeral 19 denotes a negative / positive switching switch, which connects the movable contact piece 23 to the contact 24 side when the negative film is photographed, and connects the movable contact piece 23 to the contact 25 side when the slide film is photographed or at the time of normal photographing.

Reference numeral 25 is a switch for switching the white balance adjustment to the first method, which is a constant value. When the movable contact piece 20 is connected to the contact 21 side, the switch is the first method, and when the movable contact piece 20 is connected to the contact 22 side, the switch has a constant value. Become.

The operation of the conventional video camera thus configured will be described.

During normal shooting, the movable contact piece 23 of the negative / positive (N / P) reversing switch 19 is connected to the contact 25 side, and
When the white balance is adjusted by the tracking type, the movable contact piece 20 of the switch 25 is connected to the contact 21 side.

The optical information of the subject incident on the image sensor 1 via the lens 1 is photoelectrically converted, and the photoelectrically converted signal extracted by scanning is input to the preamplifier 2 where the weak signal input here is amplified. The video signal is input to the luminance / color signal separation circuit 3. The luminance / color signal separation circuit 3 separates and extracts the input video signal into a luminance signal y and a color signal C, the luminance signal y is input to the process circuit 5, and the color signal C is input to the color separation circuit 4. It The process circuit 5 negatively (N / P) the input luminance signal y.
The low-frequency luminance signal y _L from the luminance signal y is input to the process circuits 6 and 7 while being input to the inverting circuit 5. The color separation circuit 4 separates and extracts the R signal and the B signal from the input color signal C, and inputs the R signal to the process circuit 6 and the B signal to the process circuit 7.

On the other hand, light from the outside is incident on the red light detecting filter 9a and the blue light detecting filter 9b through the scattering plate 8, the red light is photoelectrically converted by the photodiode 10a, amplified by the amplifier 11a, and the blue light is converted. It is photoelectrically converted by the photodiode 10b and amplified by the amplifier 11b. Next, the R and B signals logarithmically converted by the logarithmic arithmetic circuits 12a and 12b are input to the subtractor 12c,
The obtained color temperature signal is supplied to the process circuit 7 and the inverting amplifier 1.
It is added to the process circuit 6 inverted by 3, and the gains of the process circuits 6 and 7 are adjusted to perform white balance adjustment.

The output signal R-y _{L of the} process circuit 6 and the process circuit 7
Output signal B-y _L of the negative polarity (N / P) inversion circuit 15 is input to the color modulation circuit 14.
Input to the encoder 16 via the output terminal 26
Outputs color signals converted to SC format.

Next, a case where a DP adapter (not shown) is attached to a video camera to affect a film or a slide film will be described. The movable contact piece 20 of the switch 25 is switched to the contact side 22 and connected to the power supply 26, and its voltage is changed. Is applied as a color temperature signal to the process circuit 7 and the voltage inverted by the inverting amplifier 13 to the process circuit 6 to maintain their gains at constant values and perform white balance adjustment. Also,
The movable contact piece 23 of the switch 19 of the negative / positive (N / P) inversion circuit 15 is connected to the contact 24 side when film photographing is performed, and is connected to the contact 25 side when slide film photographing is performed.

In this way, the film or slide film is photographed by the video camera, but since the operation of the circuit device is the same as that in the case of the normal photographing described above, the description thereof will be omitted.

For this type of video camera, does the operator perform tracking type white balance control by operating the switch?
It is necessary to correctly determine whether or not the setting type white balance control is performed. In addition, the color temperature of the light source used when shooting a film or slide film changes depending on the type of light bulb used, aging, etc.The color of the base material of the film or slide film also depends on the type and manufacturer. Because of the difference, when the white balance adjustment value is fixed to a fixed value as described above, the white balance cannot be adjusted in response to the change in color temperature, and thus the image with good color reproducibility can be obtained. There was a drawback that I could not.

〔Purpose〕

The present invention solves the above-mentioned drawbacks of the prior art, and when the film DP adapter is attached, the white balance is adjusted by the first method, or the white balance is inaccurate due to a mere constant value. It is an object of the present invention to provide a video camera that does not make adjustments.

[Explanation by Examples]

Hereinafter, means taken by the present invention for solving the above-mentioned object will be illustrated and described with reference to the drawings.

[Explanation of FIG. 2] FIG. 2 shows a block circuit of an essential part of an embodiment of the video camera of the present invention.

In FIG. 2, the components having the same reference symbols as the components shown in FIG. 1 have the same structure and the same function as those shown in FIG. .

Reference numeral 30 denotes a switching device capable of switching to the white balance adjustment of the first method (first mode) or the second method (second mode), which includes the movable contact piece 30a and the contact 30.
b, 30c, 30d, 30e, and movable contact piece 30a
When connected to the contacts 30c and 30e, the auto white balance circuit 31 and the process circuits 6 and 7 which will be described later are connected to each other to adjust the white balance in the second mode, and the movable contact piece 30a is connected to the contacts 30b and 30d. , The subtractor 12c in FIG. 1 is connected to the process circuit 7, and the subtractor 12c is connected to the process circuit 6 via the inverting amplifier 13 to adjust the white balance in the first mode. Become. Reference numeral 36 denotes a switch for selecting the white balance between the first mode and the second mode, and a detection switch for detecting the presence or absence of the operation of the switch 36 and the presence or absence of the DP adapter input to the OR gate 35. If the output is at a high level, the switching contact piece 30a of the switching device 30 is connected to the contact point 30c.
And 30e in the second mode, and when the output is at a low level, the movable contact piece 30a of the switching device 30 is connected to the contacts 30b and 30d to adjust the white balance in the first mode. A switch 34 detects whether or not the DP adapter is attached. It outputs a low level signal when the DP adapter is not attached, and a high level signal when the DP adapter (not shown) is attached at the attachment position 34a shown by the dotted line. Is output and input to the OR circuit 35.

An auto white balance circuit 31 includes, for example, a comparator, a digital counter, and a DA converter inside. A switch 32 has a contact 33.
The digital counter operates by connecting to the comparator, so that the color difference signal R-y _L input from the process circuit 6 and the color difference signal B-y _L input from the process circuit 7 become zero respectively. Digital counter, D
An error voltage is applied to the process circuits 6 and 7 via the A converter to control the gains thereof, and the gains of the process circuits 6 and 7 are made constant when the color difference signals R-y _L and B-y _L become zero. Hold the value and adjust the white balance in the second mode.

The video camera configured in this way can be
The following describes how to adjust the white balance by switching between the mode 2 and the second mode.

At the time of normal photographing, the movable contact piece 23 of the switch 19 of the negative / positive (N / P) inversion circuit 15 is connected to the contact 25, and the selection switch 36 for switching the white balance adjustment to the first mode or the second mode. To open. Since the DP adapter is not attached, the output signal from the detection switch 34 is at low level, all the signals input to the OR gate 35 are at low level, and accordingly, the output of the OR gate 35 is at low level. Therefore, the switching device 30 is not energized, and the movable contact piece 30a thereof has the contact 30
Connected to b and 30d, the white balance of the first mode can be adjusted. This will be described. Optical information from a subject incident on the image sensor 1 through the lens 1 is photoelectrically converted by the image sensor 1, and a video signal extracted by scanning is input to a preamplifier 2 and amplified. It is later input to the luminance / color signal separation circuit 3. The luminance signal y separated and extracted by the luminance / color signal separation circuit 3 is input to the process circuit 5, the low-frequency luminance signal y _L separated and extracted here is input to the process circuits 6 and 7, and then the luminance signal y. Is input to the negative / positive (N / P) inversion circuit 15. The color signal C separated and extracted by the luminance / color signal separation circuit 3 is a color signal separation circuit 4
The R signal that is input to and separated and extracted is input to the process circuit 6
, And the B signal is input to the process circuit 7.

On the other hand, the light from the outside irradiates the diffuser plate 8, the light diffused by the diffuser plate 8 irradiates the red light detecting filter 9a and the blue light detecting filter 9b, and the red light is converted into an electric signal ( R) is converted and inputted into the amplifier 11a, and the blue light is converted into an electric signal (B) by the photodiode 10b and inputted into the amplifier 11b. Amplifier 1
The R and B signals amplified by 1a and 11b are logarithmically converted by logarithmic operation circuits 12a and 12b and then input to a subtractor 12c, and the color temperature signal obtained here is processed by a process circuit 7 and an inverting amplifier 13. Through process circuit 6
The gain of the process circuits 6 and 7 is changed in accordance with the change in the color temperature of the light radiated to the diffuser 8 and the white balance of the first mode is adjusted.

Color difference signals R-y _L output from the process circuits 6 and 7,
After B-y _L is input to the color modulation circuit 14 for modulation, the color signal C is input to the negative / positive (N / P) inversion circuit 15 and converted into an NTSC color signal in the encoder 16. , To the output terminal 26.

When an attempt is made to adjust the white balance in the second mode during shooting while the white balance is adjusted in the first mode, the switching switch 36 is closed. As a result, a high level signal is input to one terminal of the OR gate 35, but a low level signal from the detection switch 34 is input to the other terminal of the OR gate 35 because the DP adapter is not attached. Accordingly, the OR gate 35 outputs a high level signal, which is applied to the switching device 30 to be energized, and its movable contact piece 30a is connected to the contacts 30c and 30e to adjust the white balance in the second mode. Can be done. When the white balance is adjusted in the second mode, the switch 32 is connected to the contact 33.

To adjust the white balance in the second mode, a white paper is placed in front of the lens l or covered with a white cap, and the optical signal at this time is made incident on the image sensor 1.
The color difference signal R-y _L from the process circuit 6 and the color difference signal B-y _L from the process circuit 7 thus obtained are input to the auto white balance circuit 31. By connecting the switch 32 to the contact 33, the digital counter in the auto white balance circuit 31 starts to operate,
The error voltage controls the gains of the process circuits 6 and 7 through the comparator, the digital counter, and the DA converter so that the input color difference signals R−y _L and B−y _L become zero, respectively. At this time, the gains of the process circuits 6 and 7 are held at constant values.

In this way, during normal shooting, the white balance adjustment can be switched from the first mode to the second mode, or from the second mode to the first mode depending on the situation.

Next, the white balance adjustment in the second mode when shooting a film or a slide film using a video camera will be described.

When the DP adapter (not shown) is mounted at the mounting position 34a shown by the dotted line, the detection switch 34 outputs a high level signal, which is input to the other terminal of the OR gate 35. A low level signal is input to one terminal of the OR gate 35 when the selection switch 36 is open, and a high level signal is input when the selection switch 36 is closed.
A high level signal is output irrespective of whether the movable contact piece 30a is in contact with the contact 3
0c and 30e so that the white balance in the second mode can be adjusted.

The negative / positive (N / P) inversion circuit 15 connects the movable contact piece 23 to the contact 24 when photographing a film, and connects the movable contact piece 23 to the contact 25 when photographing a slide film. The film or slide film can be accurately recorded.

In this way, simply by attaching the DP adapter to the video camera, the white balance adjustment is automatically switched to the second mode, and good white balance adjustment can be performed when shooting a film or slide film. it can.

In the embodiment described above, when the film is photographed, the color temperature of the edge of the film is separately detected,
It is also possible to add this color temperature to the white balance adjustment circuit to compensate for the color temperature of the color of the film itself based on the difference in the type of film.

〔effect〕

According to the present invention, in the white balance system having the color temperature detecting means, the white balance adjustment is performed by using the output of the image capturing means instead of the color temperature detecting means as the DP adapter is mounted on the image capturing means. Since it is configured as described above, it is possible to solve the problem that the white balance adjustment is performed by using the output of the color temperature detecting means when the DP adapter is attached. Further, since the white balance mode using the output of the image pickup means is switched when the DP adapter is attached to the image pickup means, there is no problem that the operator selects the wrong white balance mode.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional video camera, and FIG. 2 is a block diagram of an embodiment of the video camera of the present invention. In the figure, 1 is an image sensor, 2 is a preamplifier, 3 is a luminance / color signal separation circuit, 4 is a color signal separation circuit, 5, 6, 7
Is a process circuit, 14 is a color signal modulation circuit, 15 is a negative / positive (N / P) inversion circuit, 16 is an encoder, 26 is an output terminal, 8 is a diffusion plate, 9a and 9b are filters, 10
a and 10b are photodiodes, 11a and 11b are amplifiers, 12a and 12b are logarithmic arithmetic circuits, 12c is a subtractor,
13 is an inverting amplifier, 30 is a switching device, 34 is a DP adapter detection switch, 34a is a mounting position of the DP adapter,
Reference numeral 35 is an OR gate, 36 is a switching switch, and 31 is an auto white balance circuit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-58-225792 (JP, A) JP-A-58-210782 (JP, A) JP-A-58-147721 (JP, A)

Claims (1)

[Claims] 1. An image pickup means for converting subject information into an electric signal, a plurality of gain control means for controlling gains of a plurality of color signals output from the image pickup means, and the image pickup means at the time of photographing a negative or a positive film. A first white balance for adjusting the white balance by controlling the DP adapter attached to the device, the detection means for detecting the color temperature of the subject, and the gain control means according to the output of the detection means. A white balance adjustment unit having a mode and a second white balance mode for performing white balance adjustment by controlling the plurality of gain control units according to the output of the image pickup unit, and the DP adapter as the image pickup unit. A switching hand that selects the second white balance mode in the white balance adjusting means as the user wears it. Video camera and having a, the.