JPH01191595A - Color reproduction control method for video printer - Google Patents

Abstract

PURPOSE:To control the color reproducibility of a monitor or a printer as desired irrespective of an input signal to an A/D conversion part by adjusting an input signal to the A/D conversion part based on the result of a comparison between reference data and a digitized input signal. CONSTITUTION:The comparison between input signals that are digital RGB signals and the reference data already stored in an internal memory i.e., for instance, coloring, white balancing, and brightness is executed in a control part 8a. Adjustment data corresponding to the result of said comparison is calculated, converted to an analog amount by a conversion circuit 9, and based on it, an input signal after undergoing a decoding part 2 is adjusted analog-wise by an adjustment circuit 10. Since an input signal to a video printer is thus compared with the reference data, the coloring, white balancing, brightness i.e. the color reproducibility can be controlled as desired at the time of monitoring or printing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video printer that controls color reproduction during monitoring and printing based on input signals, and more specifically relates to a video printer that controls color reproduction by input signals and pre-stored reference data. Compare,
The present invention relates to a color reproduction control method for a video printer in which color reproduction is adjusted by adjusting an input signal to a predetermined value based on the comparison result.

[Conventional example] In recent years, various manufacturers have been proposing video printers that input television signals, video signals, etc., and print one still image using that signal. Moreover, many color video printers that perform color printing have been proposed, and this has led to the further spread of video printers.

By the way, the above video printer has a configuration as shown in FIG. 2, for example, and receives an image signal (video signal) from the camera 1 as its input.

In the figure, the video signal is converted into RGB by the decoder section 2.
The signal is converted into a signal and further converted into a digital signal by the A/D converter 3. When the video printer is being operated as a monitor, the digitally converted RGB signals are not stored in the frame memory 4, but are converted into analog signals in the D/A converter 5, and then converted into analog signals in the encoder 6. and is output from a video output terminal (not shown). Therefore, by connecting a monitor device to the video output terminal, images captured by the camera 1 can be monitored on the monitor device.

Further, when the video printer is performing a recording operation, the RG data converted into digital data by the A/D converter 3 is
One still picture based on the B signal is stored in the frame memory 4. Subsequently, when the video printer performs a printing operation, one still image stored in the frame memory 4 is read out for each print line, and further one still image is read out for each color. and output to the printer section 7. As a result, the printer section 7 prints one still image stored in the frame memory 4 line by line and for each color.

The control unit (CPU) 8 performs various controls when the video printer performs monitoring, recording, and printing operations.

[Problems to be Solved by the Invention] By the way, the camera 1 that outputs the video signal is equipped with an adjustment function such as an aperture according to the illumination condition of the subject, but the video signal to which the video signal is input is - The reality is that printers are not equipped with such adjustment functions. Therefore, the video printer described above can only monitor and print based on the input signal, and cannot adjust color reproduction.

Therefore, the color reproducibility of monitors and prints based on video signals etc. from the camera 1 greatly depends on the color characteristics of the camera 1. For example, if the location where the camera 1 is taking images is not under optimal lighting conditions, For example, when it is dark, the only option is to increase the sensitivity of the camera 1, and the color reproduction on the monitor or prints may not be sufficient, resulting in poor image quality on the monitor or prints.

The present invention has been made in view of the above problems, and its purpose is to provide a color reproduction control method for a video printer that allows the color reproduction of monitors and prints to be controlled as desired regardless of the input signal. There is a particular thing.

[Means for Solving the Problem] In order to achieve the above object, a color reproduction control method for a video printer according to the present invention converts an input signal such as a video signal from a camera into a digital signal by an A/D converter. Then, one still image is stored in the frame memory from that input signal, and this one still image is stored in the frame memory.
A video device in which a still image is printed by a printer section, and the digitally converted input signal or one still image stored in the frame memory is converted into analog by a D/A converter section and output to a monitor device, etc. - In the printer, the pre-stored reference data is compared with the input signal converted to digital by the A/D converter, and based on the comparison result, the input signal is converted to digital by the A/D converter. The input signal is adjusted to a predetermined value, and color reproduction is controlled in terms of hue, white balance, brightness, etc. during printing on the monitor in the monitor device and in the printer section.

[Example] Hereinafter, an embodiment of the present invention will be described based on FIG.

In the figure, the same parts as in FIG. 2 are denoted by the same reference numerals, and redundant explanation will be omitted.

In the figure, the RGB signals of the input signal digitally converted by the A/D conversion section 3a are also input to the control section 8a. The control section 8a includes
Standard data is stored, and the system is equipped with a function to compare this standard data with the digitally converted RGB signal, and output the difference as adjustment data according to the comparison result. . Note that the A/D conversion section 3a and the control section 8a are also provided with the same functions as the A/D conversion section 3 and the control section 8 shown in FIG. 1, respectively.

The conversion circuit 9 is equipped with a D/A converter etc. that converts the adjustment data output from the control section 8a into an analog quantity, and the adjustment circuit 10 converts the RGB signal that has passed through the decoder section 2 based on the analog quantity. adjusted, and the A/D converter 3
It is output to a.

Next, the operation of the color reproduction control method applied to the video printer configured as described above will be explained.

First, when the video printer performs an operation to obtain reference data, when the subject adjustment plate (for example, a white board) 0 is photographed with camera 1,
A video signal output from the camera 1 is input. At this time, the adjustment switch is turned OFF, the input signal is converted into an RGB signal by the decoder section 2, and the input signal is converted into an RGB signal by the A/D converter section 3.
The signal is converted into digital data at step a and input to the control section 8a. In the control section 8a, reference data such as color data, etc. based on the RGB signals from the adjustment plate 0 are stored in a predetermined area of the internal memory. In this way, the reference data is created and the control unit 8
stored in the internal memory of a.

After that, in order to monitor other subjects photographed by camera 1, the video printer is operated for monitoring, the adjustment switch is turned on, and the control section 8a inputs the digital RGB signal from the input signal and the digital RGB signal already stored in the internal memory. Comparisons are made with reference data, for example in terms of hue, white balance, and brightness. Adjustment data is calculated according to the comparison result, and this adjustment data is converted into an analog amount by the conversion circuit 9 and then converted into an analog amount by the adjustment circuit 10.
is input. Based on the adjustment data, the adjustment circuit 10
The input signal that has passed through the decoder section 2 is adjusted in an analog manner. That is, the location where the subject is photographed by camera 1 is not under optimal lighting conditions.

For example, if it is dark or there is a bias in the spectral distribution of the illumination light, the darkness or the bias is adjusted analogously to the video signal output from camera 1, and at this time, the color tone is also adjusted. .

Therefore, the image of the subject taken with camera 1 is always the same as under the optimal lighting conditions, and when you print a still image from a monitor or from that 1 still image, you can obtain an image with extremely good color reproduction. . Note that the calculation of the adjustment data is executed not only at -degrees but also every time the input signal is present.

In this way, the input signal of the video printer can be compared with reference data, and color reproduction such as hue, white balance, brightness, etc. can be controlled as desired during monitoring or printing.

In the above embodiment, the color reproducibility is adjusted before the A/D converter 3a, but it may be adjusted after the A/D converter 3a. In this case, the conversion circuit 9 is no longer necessary, and the adjustment circuit 10 is placed after the A/D conversion section 3a.

[Effects of the Invention] As explained above, according to the color reproduction control method for a video printer of the present invention, pre-stored reference data and the input signal digitally converted by the A/D converter are Based on the comparison result, the input signal to be converted into a digital signal by the A/D converter is adjusted to a predetermined value, and the hue, white balance, and brightness are adjusted in accordance with the results of the comparison. Since we controlled color reproduction from points such as
For example, if the location where camera 1 is taking a picture of a subject is under poor conditions, the video signal output from that camera can be adjusted using adjustment data, and the adjusted video signal can be used to adjust the color tone, whiteness, etc. when monitoring or printing. Color reproducibility such as balance and brightness can be adjusted as desired.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a schematic block diagram of a video printer to which a color reproducibility control method is applied, and FIG. 2 is a schematic block diagram of a conventional video printer. In the figure, 1 is a camera, 2 is a decoder section, and 3 and 3a are A/D
4 is a frame memory, 5 is a D/A converter, 6 is an encoder section, 7 is a printer section, 8.8a is a control section (CPU), and O is an object (adjustment plate, etc.).

Claims (3)

[Claims] (1) An input signal such as a video signal from a camera is converted into digital data by an A/D converter, one still image from the input signal is stored in a frame memory, and the one still image is printed by a printer. At the same time, in a video printer that converts the digitally converted input signal or one still image stored in the frame memory into analog in a D/A converter and outputs it to a monitor device, etc., the pre-stored standard is used. Comparing the data with the input signal digitally converted by the A/D converter, and adjusting the input signal digitally converted by the A/D converter to a predetermined value based on the comparison result; A color reproduction control method for a video printer, characterized in that color reproduction is controlled in terms of hue, white balance, brightness, etc. when printing on a monitor in the monitor device and in the printer section. (2) The color reproduction control method for a video printer according to claim 1, wherein the reference data is obtained by digitally converting a video signal from a reference adjusting plate in the A/D converter. (3) A control unit that performs the comparison process and outputs adjustment data according to the comparison result, a conversion circuit that converts the adjustment data into an analog quantity, and adjusts the input signal using the analog quantity. 2. A color reproduction control method for a video printer according to claim 1, further comprising an adjustment circuit.