JPS59219088A - Method and apparatus for color image pickup using video information - Google Patents

Abstract

PURPOSE:To bring the color tone of a color hard copy close to the color tone of a color display by providing a main exposure step and a mixed color exposure step. CONSTITUTION:R, G, B video signals from a color display inputted to a CRT monitor 2 are displayed sequentially on a screen 3. This picture is exposed on a film 8 via a rotary filter 7 provided with R, G, B filters and a lens 9. Further, the rotary filter 7 is controlled for turning so as to apply a filter of the same color (main exposure step) respectively to a video signal by color. Then signals different in color at each filter, e.g., G and B signals are displayed on a monitor (mixed color exposure step) for a present time respectively. This is repreated for the G, B filters similarly. The color tone of the color hard copy is frought close to the color tone of the color display limitlessly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for creating a color hard copy based on a video signal of a color display, and particularly relates to a device for creating a color hard copy based on a video signal of a color display.
The present invention relates to a method and apparatus for high-fidelity color reproduction using an additive coloring method of three primary colors of blue.

In recent years, color display devices have made remarkable progress and are now being used in various fields. Examples include color display of medical images, color display of remote sensing data, and color display of all designs and animation sites. Unlike the color displays used in general office automation (OA) equipment, these require extremely high color development characteristics, and naturally, high-fidelity color reproduction is essential for these hard copies as well. Recently, I have been projecting R-G-B signal images from a color display onto a black-and-white cathode ray tube (hereinafter referred to as a monochrome CRT) in time sequence, and combining them with corresponding R-G and B filters. 2. Description of the Related Art Apparatuses for producing high-fidelity color hard copies by superimposing exposure on a single color film have been put into practical use and have become widespread. As shown in Fig. 1, this device outputs video signals obtained from a still image by R@G-B in a color graphic display device (not shown) by sequentially switching each color at least one frame at a time. A video signal switch 1 and a black-and-white cathode ray tube display device (hereinafter referred to as a CRT monitor) 2 that sequentially displays video signals from the switch 1.
, the color-coded image 3 displayed on the CRT monitor 2 is displayed in R(
A camera lens 9 for projecting a video onto an instant color film 8 such as a Polaroid photo via a rotating filter 7 comprising a red) filter 4, a G (green) filter 5 and a B (blue) filter 6; Signal switch 1
, a timing controller 10 that synchronizes and controls the CRT monitor 2 and rotary filter 7. In such a color teit shadow device, video signals obtained separately for R, G, and B are sequentially CR-recorded for each color at least one frame at a time.
Color reproduction is performed by displaying a black and white image on the T-monitor 2 and exposing it three times to a sheet of instant color film 8 through a corresponding color filter 4.5 or 6 according to the color. be. R-G with
-It is an additive color photographing device that uses color film 8
By selecting the three primary color (R-G and B) separation filters 4.5 and 6 according to the spectral characteristics of the spectral characteristics, bright color development without color mixture can be obtained. Furthermore, regarding the difference in spectral sensitivity for the three primary colors of color film 8, the exposure time is R/G-1.
If each one is appropriately selected, a color hard copy with a tone faithful to the video signal can be obtained. But is it enough to create a color hard copy that is faithful to the color tone of a color display? I can't do it. That is, the color tone of a color display is controlled by the coloring characteristics of the R.G-I3 phosphor of the color cathode ray tube used, and this is the standard for the coloring of the glass display. On the other hand, the color tone of a color hard copy is controlled by the magenta, cyan, and yellow coloring characteristics of the color film used, so no matter how faithful the signal is to the hard copy,
In reality, there was a drawback that the color tone was slightly different from that of a color display.

Originally, this type of color hard copy device recorded images projected on a color display.

It is desirable that the color tone of the color hard copy be as close as possible to the color tone of the color display. It is particularly strong (desired) in the fields of medical imaging and apparel design.

The present invention was made in view of the above circumstances, and its purpose is to improve the color tone of a J-color hard copy in a device that photographs color film using a three-primary-color sequential exposure method based on a video signal from a color display. The object of the present invention is to provide a method for bringing the color tone as close as possible to that of a display, and an apparatus for carrying out this method.

To achieve this object, the present invention displays a color video signal from a color display on a black and white cathode ray tube in different colors, and sequentially displays the screen of the cathode ray tube on a color film through color filters. In a color photographing method and apparatus having an exposure cycle that performs multiple exposures, in addition to the main exposure cycle in which the video signal and the color filter are made to correspond, there is also a signal of two other colors that do not correspond to the color filter, or a signal that corresponds to the color filter. Including a mixed color exposure cycle in combination with two other color filters,
After adjusting the gain of the video signal in the main exposure cycle and the mixed color exposure cycle by the voltage adjustment means,
This gain-adjusted video signal is controlled by a timing controller so that the mixed color exposure step is not performed after the main exposure step for each of the three primary colors, and the color video for each color is mixed, thereby producing color for the color hard copy (
The idea was to make it possible to adjust the color tone to bring it as close as possible to the color tone of a color display.

The details of the present invention will be explained below with reference to FIGS. 2 to 7. 2 to 4 are chromaticity diagrams for explaining the present invention in detail. Figure 2 is a chromaticity diagram of CUE (International Commission on Illumination). This chromaticity diagram shows the colors of the natural world as a horse-shaped region on the X-Y coordinates. The mixed color lies on the straight line connecting the position coordinates of the two colors. Further, a mixture of three arbitrary colors is inside a triangle whose vertices are the position coordinates of each of the three colors. This second
According to the diagram, red is used in color displays,
Red, green, and blue color coordinates obtained by 111 combination of the color coordinates of each emitted color produced by the phosphor consisting of the three primary colors of green and blue, and the cyan, magenta, and yellow of the filter surface film of a color photographing device. If they match, the hue of the hard copy obtained by shooting on film will be the same as that of the image by making the ratio of the red, green and blue signals supplied to the CRT monitor the same as that of the color display. It can be seen that the hue is almost the same.

However, as shown in Figure 3, if we separate the coloring area of a color display from the coloring area of a combination of fill and film in the second part of the C'IE chromaticity diagram, the coloring area of a color display generally differs from that of a filter. Compared to the coloring area created by the combination of films, only a narrow area is visible (
-I can see that it is not being used. This is due to manufacturing limitations of the phosphors used in color displays. In this way, there is a slight deviation in the hue between the color display and the color hard copy obtained by exciting the three primary colors, each with a slightly different hue, with the same signal amount. There was no way to make any corrections.

The present invention converts color video signals into monochrome CRTs by color classification.
, and in each exposure cycle when this CRT screen is sequentially photographed on color film through color-specific color filters, each of the primary colors constituting the three primary colors is mixed with a small amount of the other two colors. As a result, the coordinates on the CIE chromaticity diagram of the film color development at each exposure step of the color photographing device are matched with the coordinates of the emission color of the corresponding phosphor of the color display, and as a result, the color obtained with the color photographing device is This is to ensure that the hard copy produced has the same hue as the color display that serves as its reference.

A specific example of a method for matching the color development of a hard copy with the color development of a color display will be explained using FIG. 4.

Note that FIG. 4 shows the process for matching green colors. In the same figure, 31, 32, and 33 indicate the green, red, and blue hues of the photographing device determined by the combination of the filter and color film, respectively, and 35.3G and 37 indicate the green, red, and blue hues of the color display. Indicates hue. Now, when we want to match the green 31 of the photographing device to the green 35 produced by the Y color display, we first match the green 31 with the red 32.
A straight line connecting green 31 and red 32 by slightly mixing the
Change the hue at position 4 to green. Then this 34
The hue of 35 on the straight line connecting 34 and 33 is obtained by slightly mixing blue 33 with the color of , that is, green 35, which is the color of the color display.
can be matched to the hue of The mixing ratio of these three colors is determined by comparing the hues of experimentally photographed prints and color displays (however, once the mixing ratio is determined, as long as the same film and color display are used for shooting), It is possible to obtain colors of the same hue with good reproducibility without changing the mixing ratio in any way.If you use the same method to match the hues of the photographing device and color display for the remaining red and blue, you can obtain the final color. In this way, the color produced by the photographing device and the color produced by the color display can be perfectly matched.

In addition, the coordinates of the emitted color of the phosphor of a color display,
If the color is located outside the triangle formed by the three primary colors obtained by the combination of filter and film, the color coordinates of the color film in each exposure cycle are the same as the coordinates of the color emitted by the phosphor of the color display. Although it is theoretically impossible to By doing so, it is possible to obtain the same effect.
Next, an embodiment of the color photographing apparatus according to the present invention will be described in detail with reference to FIGS. 5 to 7.

FIG. 5 is a block diagram of a color photographing device using video information, which is an embodiment of the present invention. In FIG. 5, parts corresponding to those in FIG. 1 are given the same reference numerals.

From the still image to be photographed displayed on a color graphic display device (not shown), R-G-B
The separately obtained video signal is input to the video signal switching device 1, and is sequentially switched for each color at least every 61 frames and output to the voltage adjustment means 20. This switching is performed by a switching command signal from the timing controller 10, but the spectral sensitivities of the color film 8 for the three primary colors are not necessarily the same, and therefore the exposure time is changed according to the spectral sensitivity of each R-G or B. , the timing controller 10 controls the number of frames corresponding to the exposure time to be transmitted for each color.

The voltage adjustment means 20 includes 7-channel voltage regulators 21 to 7 channels.
27, one channel for the main exposure cycle,
Six channels are allocated for the mixed color exposure cycle. These voltage regulators 21 to 27 each include voltage adjustment dials 21d to 27d and switches 21s to 27s, and can adjust the gain in advance.

This voltage adjustment means 20 is configured such that one of the channels is selected by a command from the timing controller 10, and is configured to manually adjust the voltage amplitude of the video signal from the video signal switch 1 by manually turning the voltage adjustment dials 21d to 27d. The output can be freely adjusted by adjusting the output signal and output to a CRT monitor (black and white cathode ray tube) 2. The R-G-B separate video signals input to the CRT monitor 2 are processed by a timing controller 10.
The images are sequentially displayed on the screen 73 in synchronization with the switching of the video signal by the video signal switch 1 using a timing signal from the video signal switch 1.

The color-coded images 3 displayed on the CRT monitor 2 are R-G-
The instant film 8 is exposed through a rotary filter 7 with filters 4.5 and 6 (FIG. 1) of B and further through a lens 9. The R-G@B rotating film 7 applies filters 4.5 or 6 of the same color to the video signals of different colors in synchronization with the switching of the video signal of the video signal switch 1 by the timing signal from the timing controller 10. The timing controller 1 controls the rotation so that the signal is applied to the R filter (main exposure step), and a signal of a different color is applied to each filter.
The time set in advance to 0 is displayed on CRT monitor 2 (
color mixture exposure step). This process is repeated for the 61B filter as well.

Details of the above-mentioned main exposure cycle and mixed color exposure cycle will be further explained using the exposure cycle flowchart shown in FIG. As shown in the diagram, step 4 is outlined in a large frame.
/ a 14 / b %4 / c or 1・G-1
R-G in the main exposure cycle corresponding to each of the three primary colors of 3.
-B video signal and RG/3 filters correspond to each other.

Steps 42 and 43, 44, 45, and 4 surrounded by small frames
6 and 47 are mixed color exposure cycles, in which the R-G@B separate video signals and the R-G@8 filter are combinations that do not correspond. This example combination was adopted to minimize filter change time and combines both cycles for the same filter. Note that the symbol within the frame represents the video signal name.

Now, in the color photographing device according to the present invention shown in FIG.
When a government-provided print start switch is pressed to start photographing, a timing signal from the timing controller 10 drives a drive motor (not shown) for the rotary filter 4 to move the R filter 4 to the lens 9. Place f on the front
When the positioning of the R filter 4 is completed, the timing controller 10 outputs a video signal switching command signal to the video signal switching device 1, and the signal is obtained separately for R, -G, and B from a color graphic display device, etc. Among the video signals, the R video signal is switched over a predetermined period of time, for example, about 10 seconds, to be output to the voltage adjustment means 20.The voltage adjustment means 20 is connected to the main exposure cycle channel 21 and the mixed color exposure cycle channel 21 as described above. The main exposure cycle channel 21 is selected by the channel switching signal from the timing controller 10 at the same time as the switching of the video signal switching device 1, and the channel 21 for the main exposure cycle is selected.
The video signal is outputted to the CRT monitor 2 through the channel 21 and displayed on the screen 3.
The R video displayed on the screen passes through a filter 4 and is further exposed to an instant film 8 through a lens 9.

When the exposure by R video is completed, the timing control device]
0 switches the video signal switch 1 to output the G video signal to the voltage adjustment means 20 for a predetermined period of time, for example, about 0.8 seconds, and also switches the voltage adjustment means 20 to output the G video signal for the filter.
Select video color mixture exposure channel 22, CRT monitor 2. The color film 8 is exposed through the R filter 4 and the color film 8 through the R filter 4 and the laser beam O. When the color mixing exposure using the G video is completed, the timing controller 10 further switches the video signal switch 1 to output the B video signal for a predetermined period of time, for example, approximately 0.8
The voltage is outputted to the second voltage adjustment means 20, and the voltage adjustment means 20 is switched to select the B video mixed color exposure channel 23 for the R filter, and the color film 8 is exposed in an overlapping manner in the same manner as described above. After the main exposure and color mixture exposure steps for the R filter 4 are completed, the timing controller 10 drives the rotary filter drive motor to position the G filter 5 in front of the lens 9.
Once the positioning of the G filter 5 is completed, in the same way as in the step for the R filter 4, the G video signal is transmitted through the main exposure cycle channel 21 of the voltage adjustment means 2o, and the R video color mixing exposure channel for the G filter is transmitted. 24 and G
R via B video color mixing exposure channel 25 for filter
The video signal and the B video signal are each displayed on a CRT monitor 2, and are exposed onto a color film 8 through a G filter 5 in an overlapping manner. When the exposure step for the G filter 5 is completed, the B filter 6 is also exposed in the same way, but the channel used by the voltage adjustment means 2° is the main exposure cycle channel 2 for the B video signal.
1. For the R video signal, the R video color mixture exposure channel 26 for the B filter is used, and for the G video signal, the G video color mixture exposure channel 27 for the B filter is used. Note that the main exposure time and mixed color exposure time for the G filter 5 and the B filter 6 are the same as the exposure time for the R filter. When the exposure of the B filter 6 is completed, the timing controller 1o outputs a drive timing signal to the drive motor of the rotary filter 7 to rotate the rotary filter 7 to the shutter position.

Each control timing of the above-mentioned timing controller 1o is shown for reference in FIG. A color hard copy can be obtained by superimposing and exposing an R@G-B signal image from a color display onto a single color film 8 through a series of exposure cycles.

In the two series of embodiments, the mixed color exposure cycle is performed by combining signals of two other colors that do not correspond to the color filter, that is, the G and B video signals when R filter 4 is applied, and the G and B video signals when R filter 4 is applied.
A case has been described in which a combination of R and B video signals is applied with filter 5 and R and G video signals are applied with B filter 6, but this color mixture exposure cycle does not correspond to the video signal. It can also be carried out using a combination of other two color filters. That is, in the above embodiment, control was performed so as to sequentially provide video signals of three colors to one color filter, but when the video signals are displayed on the CRT monitor 2 in order of color,
The same result as described above can be obtained by controlling the rotation of the rotary filter 7 so as to sequentially apply the three color filters 4, 5 and 6 for each color.

As is clear from the above description, according to the present invention, the R-G-Bv! color cathode ray tube! Corrects subtle differences between the color tone of a color display, which is governed by the coloring characteristics of the light source, and the color tone of a color hard copy, which is governed by the magenta, cyan, and yellow coloring characteristics of the color film. It is now possible to get closer to the color tone of a color display.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram showing a conventional R-G-n additive color photographing device, Figure 2 is a chromaticity diagram of the International Institute of Illumination, and Figure 3 is a color display diagram on the chromaticity diagram of Figure 2. FIG. 4 is a diagram showing the coloring area and the coloring area by the combination of filter and film, and is for illustrating the principle of the present invention, and is a diagram showing a method for matching the coloring of a hard copy to the coloring of a color display. , FIG. 5 is a block diagram showing a color photographing device using video information which is an embodiment of the present invention, and FIG.
The figure is a flowchart showing the exposure cycle of the apparatus shown in FIG.
FIG. 7 is a diagram showing each control timing of the timing controller in the apparatus shown in FIG. 5. l...Video signal switch, 2...CRT monitor, 3...
Screen, 7 Rotating filter, 8 Color film, 9 Camera lens, IO Timing controller, 20 Voltage adjustment means Patent applicant Nippon Avionics Co., Ltd. Figure 1 Figure 2 Figure 5 Figure Seat 4 Figure 6 Figure Thread 7 Figure

Claims (4)

[Claims] (1) In a color photographing method in which a color video signal is displayed on a black-and-white cathode ray tube according to color, and an exposure cycle is performed in which the screen of the cathode ray tube is sequentially photographed onto a color film through a color filter. In addition to the main exposure cycle in which the video signal and color filter correspond to each other, it also includes a mixed color exposure cycle in which two other color signals that do not correspond to the color filter or a combination of two other color filters that do not correspond to the signal are used. A color photography method characterized by: (2) The exposure time of each signal in the mixed color exposure cycle is sufficiently shorter than the exposure time of each signal in the main exposure cycle, and is variable. Color photography method. (3) The cathode ray tube screen brightness of each signal in the mixed color exposure cycle is equal to or less than the cathode ray tube screen brightness of each signal in the main exposure cycle, and is variable. Color photography method. (4) An exposure cycle in which a color video signal is displayed on a black-and-white cathode ray tube in different colors using a video signal switcher, and the screen of this cathode ray tube is sequentially photographed on a color film through color filters. A color photographing device having a main exposure cycle in which the video signal and the color filter correspond to each other, and signals of two other colors that do not correspond to the color filter, or a combination of color filters of two other colors that do not correspond to the signal. voltage adjusting means for adjusting the gain (-1) of the video signal in the color mixing exposure cycle;
Using video information comprising at least a timing controller that controls the gain-adjusted current video signal to perform a color mixing exposure step after performing a main exposure step for each of the three primary colors to mix color video for each color. Color photography equipment.