JPH0255998B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for creating a hard copy image, and more particularly to a method for reproducing image information recorded on a floppy disk or the like to create a color print, that is, a hard copy, corresponding to the image information.

Conventionally, electronic still cameras have been developed that are configured by integrating a solid-state image sensor such as a CCD and a small floppy disk. When viewing images taken with such an electronic still camera, the floppy disk on which the image signals are recorded must be played back using a dedicated playback device, and the output video signals must be viewed on a monitor television. Alternatively, the photographed image can be viewed by creating a hard copy using a dot printer or the like. When making a hard copy of the reproduced video signal, the video signal is input to a dot printer to produce a color print of the same image as viewed on a monitor television. In this case, the video signal input to the dot printer is separated into three primary colors, and the level of each of the three primary colors is adjusted by printing a number of primary color dot patterns for each pixel in a ratio corresponding to the level of each primary color signal. Color mixing is performed accordingly to reproduce a color image.

However, in the conventional type, the brightness of the printed image is reproduced by adjusting the proportion of the white area by changing the number of dot patterns used in each pixel, so the color reproduction of the printed image is difficult. There was an inconvenience that my sexuality deteriorated.

SUMMARY OF THE INVENTION In view of the problems in the conventional method described above, an object of the present invention is to provide a method for creating a hard copy image.
The purpose of this invention is to improve the color reproducibility of printed images based on the concept of changing the mixing ratio of primary color dot patterns depending on the level of the luminance signal of the video signal.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a general electronic still camera. In the figure, 1 is a stripe filter of three primary colors for color separation, 2 is a solid-state image sensor such as a CCD, 3 is an amplifier, 4 is a color separation circuit, 5 is a color difference signal generation circuit, 6 is a mixing circuit, and 7 is a color separation circuit. 8 is a magnetic disk device such as a floppy disk, 9 is a disk drive circuit, and 10 is a synchronizing signal generating circuit.

In the electronic still camera shown in FIG. 1, an image of a subject is projected onto a solid-state image pickup device 2 through a color filter 1 using a lens or the like (not shown). The solid-state image sensor 2 generates an image signal corresponding to the projected image based on the synchronization pulse from the synchronization signal generation circuit 10, and the image signal is inputted to the color separation circuit 4 via the amplifier 3. The color separation circuit 4 separates the input image signal according to its phase, for example, into three primary color signals, that is, a red signal R, a green signal G, and a blue signal B, and inputs the signals to a color difference signal generation circuit 5. The color difference signal generation circuit 5 mixes these color signals at a predetermined ratio to create a luminance signal Y and color difference signals R-Y, B-Y, and inputs them to the mixing circuit 6. In the mixing circuit 6, a synchronization signal is added to the luminance signal Y, and the luminance signal and the color difference signals R-Y and B-Y are mixed and input to the FM modulator 7. In this case, the two color difference signals R-Y and B-Y are sent out alternately every horizontal scanning period. In the FM modulator 7, for example, the luminance signal Y is FM-modulated by a high-frequency carrier wave, and the line-sequential color difference signal is FM-modulated by a low-frequency carrier wave and superimposed on the low frequency side of the FM signal of the luminance signal. Ru. In this way, FM
Photographing is performed by recording the modulated luminance signal and line-sequential color difference signal on the magnetic disk 8. The disk drive circuit 9 rotates the magnetic disk at a predetermined rotational speed, for example, one rotation per 1/60 second, based on the synchronization pulse from the synchronization signal generation circuit 10.

FIG. 2 shows the configuration of an apparatus for carrying out a method according to an embodiment of the invention. In the same figure, 1
1 is a printer operation switch, 12 is a readout circuit, 1
3 is a disk playback device; 14 is a printer operating circuit; 15 is, for example, a dot-type printer; 16 is a mixing conversion circuit; 17 is a video signal waveform detection circuit;
8 is a synchronization extraction circuit, and 19 is a brightness level detection circuit.

The operation of the apparatus shown in FIG. 2 will be explained. Insert the magnetic disk on which the video signal has been recorded as described above into the disk playback device and turn on the printer operation switch 1.
By pressing 1, hard copy creation is started. In response to depression of the printer operation switch 11, the reading circuit 12 first inputs an address signal corresponding to an address specified by a keyboard (not shown) to the disk reproducing device 13.
As a result, the disc playback device 13 starts operating and plays back the video signal on the track corresponding to the input address signal. The reproduced video signal is converted into, for example, three primary color signals R, G, and B, and is input to the mixing conversion circuit 16. The reproduced video signal is also input to the video signal waveform detection circuit 17, and only the luminance signal of the video signal is detected.
The signal is input to the synchronization extraction circuit 18. Synchronization extraction circuit 1
8 extracts a synchronization signal from the input luminance signal by synchronization separation, divides the video scanning period into the number of pixels of one scanning line of the printer 15 based on the synchronization signal, and divides each divided period into The brightness signal input to the brightness level detection circuit 19 is sampled and input to the brightness level detection circuit 19. That is, brightness signals corresponding to each pixel of one scanning line of the printer 15 are sequentially input to the brightness level detection circuit 19.
The brightness level detection circuit 19 compares the input sampling signal with one or more reference voltages and classifies the brightness level of each pixel. The brightness level detection circuit 19 inputs a brightness level signal expressed, for example, in binary numbers to the mixing conversion circuit 16 according to the classified brightness level stage. Mixing conversion circuit 1
6 adjusts the gains of the three primary color signals R, G, and B based on the input brightness level signal, and changes the mixing ratio of the primary colors depending on the brightness even for colors of the same hue. In this way, the three primary colors whose gains have been adjusted are again converted into a luminance signal Y and color difference signals R-Y, R-B, and are input to the printer 15. And printer 15
is activated by the printer activation circuit 14 activated by the printer activation switch 11 that was previously pressed, and performs color printing based on the luminance signal and color difference signal thus input. In this case, the disk reproducing device 13 is operated in a low-speed reproducing mode in which the magnetic disk is rotated at a low speed according to the printing speed of the printer 15.

The operation of the mixing conversion circuit 16 described above will be explained with reference to FIG. For example, if the video signal reproduced by the disk reproduction device is green, the following operations are performed depending on whether the green is dark green, normal green, or light. That is, when the level of the luminance signal of the video signal is separated into a dark level D, a middle level M, and a light level L as shown in FIGS. 3a to 3c, and the same green color is created, cyan ( Color reproducibility is improved by changing the ratio between the number of dot patterns in c) and the number of yellow (Y) dot patterns. Figure 3a
Since the video signal has a brightness below the intermediate level M, four of the nine color dot patterns that make up one pixel are cyan (c), and the remaining five are cyan (c).
Let the number be yellow (Y). In addition, in the video signal shown in FIG. 3b, the luminance level is the bright color level L.
and the intermediate level M, 1
Of the nine dot patterns constituting one pixel, only three are cyan (c), and the remaining six are yellow (Y). Furthermore, in Figure 3c,
In a portion where the luminance signal level is equal to or higher than the bright color level L, only two of the nine dot patterns are cyan (c), and the remaining seven dot patterns are yellow (Y). Note that the color mixing ratio for other colors is similarly changed depending on the luminance. For example, red is obtained by combining magenta and yellow,
Blue can be obtained by combining magenta and cyan, but in this case as well, the ratio of the dot patterns of the mixed colors is changed depending on the brightness.

Therefore, according to the present invention, when creating a hard copy corresponding to a video signal, since the color mixing ratio is changed according to the brightness of the video signal, good color reproducibility can be achieved even when the number of pixels is small. You can get a hard copy.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the configuration of a general electronic still camera, FIG. 2 is a block circuit diagram showing the configuration of an apparatus for implementing a system according to an embodiment of the present invention, and FIG. 3 is a waveform diagram for explaining the operation of the mixing conversion circuit in the device of FIG. 2. FIG. 1...Color filter, 2...Solid-state image sensor, 3...
...Amplifier, 4...Color separation circuit, 5...Color difference signal generation circuit, 6...Mixing circuit, 7...FM modulator, 8
...Magnetic disk, 9...Disk drive circuit, 1
0...Synchronization signal generation circuit, 11...Printer operating switch, 12...Reading circuit, 13...Disc playback device, 14...Printer operating circuit, 15...
Printer, 16...Mixing conversion circuit, 17...Video signal waveform detection circuit, 18...Synchronization extraction circuit, 1
9...Brightness level detection circuit.

Claims (1)

[Claims] 1 Creation of a hard copy image that prints a color image by separating the video signal into three primary color signals, printing a number of primary color dot patterns according to the signal level of each primary color for each pixel, and mixing the colors. In the method, the color reproducibility of the printed image is improved by adjusting the color mixing ratio by changing the mixing ratio of the primary color dot pattern according to the luminance signal level of the video signal. How to create images.