JPH04247782A - Display hard copy device - Google Patents

Abstract

PURPOSE:To attain proper exposure in response to the sensitivity of a film in use and a pattern and to record a color picture with an optimum contrast on a color film by correcting the set brightness with an average brightness of a video image to be displayed. CONSTITUTION:A white level pattern is displayed when a brightness of a CRT 5 is sufficiently arisen, a brightness sensor 8 detects the white level and the level is compared with the brightness of a prescribed level, a correction voltage is outputted from a CPU 11 to an amplifier 4 so as to eliminate the brightness difference and the brightness of the CRT 5 is set to a prescribed value. Then a switch 3 is switched by a control signal from the CPU 11 and an actual video image is displayed on the CRT 5 and the sensor 8 detects the average brightness of the video image. Then the brightness is compared with the prescribed video brightness in response to the kind of the film in use and a control voltage fine-adjusting the brightness control voltage set precedingly is outputted from the CPU 11 to the amplifier 4 and the brightness of the video image displayed on the CRT 5 is adjusted to a prescribed value.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display hard copy device for making a hard copy of a display screen.

0002

BACKGROUND OF THE INVENTION Various types of display hard copy devices have been proposed, but when taking a hard copy of a color image, when taking a photograph of what is displayed on a color cathode ray tube, the RGB pixels stand out, making it difficult to take a detailed photograph. I can't take a picture. Therefore, a monochrome cathode ray tube is used, and each color of RGB is sequentially switched and displayed, and the image on the display screen is changed to RGB in synchronization with the switching timing.
There is a method in which the light is passed through a filter and the output of the filter is overlaid and exposed onto a single sheet of color film.

[0003] In a display hard copy device using this three-primary-color additive exposure method, if three-primary color separation filters are selected in accordance with the spectral characteristics of the color film, bright colors without color mixture can be obtained. Furthermore, regarding the differences in spectral characteristics for the three primary colors of a color film, if exposure times are appropriately selected for each of RGB, clear color hard copies with good color balance can be obtained.

0004

[Problems to be Solved by the Invention] However, in such conventional devices, the brightness of the screen is uniquely determined depending on the sensitivity of the color film used. Even if there were, the problem was that the dark areas would be buried in the bright areas, making it impossible to accurately record the screen.

[0005]

[Means for Solving the Problems] In order to solve such problems, the present invention provides means for displaying a white pattern on the screen, a brightness detecting means for detecting the brightness of the screen, and a method using the brightness detecting means. white level brightness setting means for adjusting screen brightness to a predetermined brightness based on the detected brightness of the white pattern; and based on the average brightness of the image detected by the brightness detection means when the image is displayed on the screen. and video brightness correction means for correcting the brightness set by the white level brightness setting means to picture brightness.

[0006]

[Operation] The brightness of the white pattern displayed on the display is detected, and based on this brightness, changes over time in the brightness of the display are corrected. After that, the average brightness of the image displayed on the display is detected, and based on this average brightness, the brightness of the display is finely adjusted to the optimal brightness according to the image, and the brightness at the video level is corrected. , a color image with optimal contrast is recorded on color film.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention. This device includes a video selector 1, a white pattern generation circuit 2, a changeover switch 3, an amplifier 4, a monochrome cathode ray tube (hereinafter referred to as a CRT monitor) 5, a rotary filter 6, a camera pack 7, a brightness sensor 8, a sync separation circuit 9, It is composed of a CRT monitor control circuit 10 and a CPU controller 11.

The video selector 1 sequentially switches and outputs video signals obtained by RGB from a still image of a color graphic display device or the like (not shown) for each color at least every frame. A changeover switch 3 switches between a white pattern generation circuit 2 that generates a white pattern, a video signal, and a white pattern signal. The amplifier 4 amplifies the video signal or white pattern signal from the changeover switch 3. A monochrome cathode ray tube (hereinafter referred to as a CRT monitor) 5 sequentially displays an amplified white pattern or video signal. The rotating filter 6 has R (red), G
(green) and B (blue) filters.

Further, 7 is a camera pack containing instant color film, etc., and 8 is a brightness sensor including a photosensor, etc., provided diagonally in front of the tube surface of the CRT monitor 5. Reference numeral 10 denotes a CRT monitor control circuit that separates a synchronizing signal from the composite video signal and controls scanning of the CRT monitor 5. 11 is a video selector 4, a white pattern generation circuit 2, a switching circuit 2, a changeover switch 3, an amplifier 4, a CRT monitor 5, a rotating filter 6, and a camera pack 7.
This is a CPU controller that synchronizes and controls the

In this device, video signals obtained separately for RGB are sequentially displayed at least one frame at a time for each color on a CRT monitor 5.
Color reproduction can be performed by displaying a monochrome image on a single sheet of instant color film three times and exposing it three times through the corresponding color filter of the rotary filter 6 according to the color.

However, since the sensitivity differs depending on the type of film used, it is necessary to match the sensitivity of the CRT monitor 5 to the film used, and when shooting, the display hard copy device is activated and the CRT monitor 5 reaches a predetermined brightness. Even if the CRT monitor 5 is photographed after a certain period of time, the brightness of the CRT monitor 5 will change over time, so it is not possible to obtain a color hard copy with good color balance.

[0012] Therefore, as shown in step 100 of the flowchart shown in FIG.
The white pattern is displayed when the brightness of the screen reaches a sufficient level. In this case, the white pattern is adjusted to have 40% or more of the entire surface of the screen white and the rest black, that is, an intermediate tone. Further, a sensor is placed at the scanning start position.

The white level of this screen is C as shown in FIG.
A brightness sensor 8 installed diagonally in front of the tube surface of the RT monitor 5
(Step 101) and compares it with a predetermined white level brightness determined in advance through experiments depending on the type of film used (Step 102).The CPU controller 11 applies a correction voltage to the amplifier 4 to eliminate this brightness difference. is output, and as shown in step 103, the brightness of the CRT monitor 5 is set to a predetermined brightness. By setting the brightness based on the white pattern, it is possible to set the brightness according to the type of film used and to eliminate changes in the brightness of the CRT monitor 5 over time.

Next, as shown in step 104, the CPU
The changeover switch 3 is switched in response to a control signal from the controller 11 to display an actual image on the CRT monitor 5, and the average brightness of the displayed image is detected by the brightness sensor 8 as shown in step 105. Then, the brightness is compared with a predetermined image brightness determined in advance through experiments depending on the type of film used (step 106), and control is performed to finely adjust the brightness control voltage previously set by the CPU controller 11 so as to eliminate this brightness difference. The voltage is output to the amplifier 4, and the brightness of the image displayed on the CRT monitor 5 is adjusted to a predetermined brightness as shown in step 107.

As a result, when the video signal has a high white level as shown in FIG. Even if there are dark areas, those areas will not be buried in the white level and will not be crushed on the film. Also, Figure 3
As shown in (b), if the black level is high, the brightness is controlled to increase, so the symbol "L"
As shown in the figure, even if there is a partially bright area, that area will be buried in the black level and will not be crushed on the film.

[0016]

Effects of the Invention As explained above, the present invention sets the brightness at which good contrast can be obtained on the film when the screen is set to a white level, and corrects this set brightness by the average brightness of the displayed image. Therefore, it is possible to perform appropriate exposure according to the sensitivity of the film used and the picture pattern, regardless of the change in brightness of the display over time, and it is possible to take a hard copy of the display with good contrast.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the device according to the present invention.

[Figure 2] Flowchart for explaining the present invention

[Figure 3
】Video signal waveform diagram

[Explanation of symbols]

1 Video selector 2 White pattern generation circuit 3 Selector switch 4 Amplifier 5 CRT monitor 6 Rotating filter 7 Camera pack 8 Brightness sensor￥ 11 CPU controller

Claims (1)

[Claims] 1. A display hard copy device for hard copying a screen on a display, comprising means for displaying a white pattern on the screen, a brightness detecting means for detecting the brightness of the screen, and a white pattern detected by the brightness detecting means. white level brightness setting means for adjusting the screen brightness to a predetermined brightness based on the brightness of the white pattern; and white level brightness setting means for adjusting the screen brightness to a predetermined brightness based on the brightness of the white pattern; 1. A display hard copy device comprising: video brightness correction means for correcting the brightness set by the level brightness setting means to picture brightness.