JPS5915367A - Picture reading device - Google Patents

Abstract

PURPOSE:To obtain a reproduced color picture in good color tones, by controlling easily and accurately the color balance of a color picture which is reproduced by a matrix array of picture elements obtained from the picture data out of a solid-state image pickup element, by making spaces between picture elements of the matrix array different for each color. CONSTITUTION:The picture data transferred synchronously with the clock pulse given from an oscillator 8 is led to an A/D converter 10 through a gate 13 and then converted into a digital picture data. At the same time, the oscillation output of the oscillator 8 is supplied to a presettable counter 16. The counted value of the counter 16 is reset every time the picture data transfer clocks are counted and the count value reaches the preset value. The preset value of the counter 16 is set at a proper value for each primary color in order to obtain a color balance which is decided by the exposure time of each primary color decided by a color separating filter 5. Then the scanning lines, i.e., the lines equal to the number of clock pulses divided with the preset value which is preset to the exposure of each primary color are thinned. Then the digital picture data is extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading/reading device equipped with a solid-state image sensor used in a digital color copying device or the like, and is particularly designed to improve the color balance of read image data.

Generally, in an image reading device such as a digital color copying machine that uses an image reading device equipped with a solid-state image sensor such as a charge-coupled device (COD), the image reading device is
Usually, as shown in FIG. 1, reflected light irradiated onto an image by an exposure lamp 1 is passed through a mirror 3 and a lens to a color separation filter! The light is focused on a solid-state image pickup device 7 which is a combination of a CCD and a CCD, and is read out to form image data.

Furthermore, as shown in FIG. The image data is converted into digital image data by a digital converter /θ, compared with a predetermined dither pattern by a dither circuit //, encoded, and then stored in a buffer memory /2.

In conventional image reading devices of this type, color separation filters j are usually provided in three types for the three primary colors R, G, and H, and when each primary color image data is read as described above, adjustment is made to 5' of the reproduced color image. In order to improve the quality or color balance, the dither pattern used in the dither circuit /l in the reading system shown in Figure 2 is made different for each primary color, and the light of the exposure lamp /l is changed for each primary color. However, it is difficult to implement because it requires the use of a dither pattern with a complicated configuration, it is difficult to select an appropriate dither pattern, and it requires delicate adjustments by Shokosha. However, there was a drawback that sufficient improvement and improvement effects were not achieved.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device that eliminates the above-mentioned conventional drawbacks and can stably and reliably improve the color balance of reproduced color images by means that are easy to implement.

The image reading device of the present invention presets the horizontal synchronization signal (H-sync) of each row of color image data to a different value for each primary color R, G, and B, divides the frequency using a counter, and reads the color image data. By varying the line spacing for each color, the color balance between each primary color can be easily improved.

The present invention will be described in detail below with reference to the drawings.

FIG. 3 shows an example of the configuration of the image reading device of the present invention.

In the image reading device having the illustrated configuration, when the operation starts, for example, from a sequence controller pufferfish that performs sequence control of a color laser beam printer,
At the timing of the start of exposure, a read signal is sent to the entire timing control circuit /j to open the gate /3.
It can also be the detection output signal. COD after receiving the reflected light from the image! The image data stored in the oscillator t and transferred in synchronization with the clock pulse from the oscillator t is amplified by the amplifier circuit 9, and then passed through the gate /3 opened as described above to be converted into an analog/digital signal. converter/
θ and converted into digital image data. Further, the oscillation output of the oscillator r is supplied to a presettable counter/B, which counts clock pulses for image data transfer and resets the numerical value d1 every time a preset value is reached.

The preset value of this counter/6 is the color separation filter j
1, for example, blue (E) fills, &? (G) Filter, Red @) In order to obtain the color balance determined by the exposure time of each primary color by the filter, set an appropriate value for each primary color.
For example, it is set by the sequence controller Pufferfish. The coincidence output signal between the counter/otsu division value and the preset value is applied to the analog/digital converter/θ as a yambbling clock, so the image that is transferred by the transfer lock is divided by the preset value. Conversion of the data into digital image signals is performed.

In other words, in contrast to the transfer lock pulse train as shown in Figure 1 (4), the oscillating clock pulses for analog-to-digital conversion are thinned out as shown in Figure 1 (B), and the digital Pixel Ma according to image data) IJ
The Fuchs array is a matrix arrangement shown by black circles in FIG.

Note that the illustrated example shows a case where the preset value of the counter /6 is set to 3.

Further, a counter is provided in the timing control circuit lj to count a1 the clock pulses for 7 lines, for example, 7
The pixel columns for a row are g lines and 17 mm, and the length of one row is 211 mm.
! mm, the built-in counter calculates 21Xf-/βt
.

When the number δ1 is counted, a horizontal synchronization signal (H-sync) is supplied to another presettable counter /If as a digital signal. This counter /g is preset to the same value as the above-mentioned counter /, and although it can be preset to a different value, the preset value and d
The coincidence output signal with the 1 value is configured to be fed back to its own reset input to perform self-reset, and is also supplied to the timing control circuit /j.

This timing control circuit /j is constructed as shown in FIG. 6, and opens and closes the coincidence output signal 3 from the counter /g. Therefore, by thinning out scanning lines equal to the number of clock pulses divided by the preset value mentioned above for each primary color exposure, digital l'1IiI@! Data is retrieved.

In the past, for example, if the line spacing of a magenta image was coarsened,
b) If the line spacing of the ICmrr image and cyan image is made finer, the number of pixels within the same area of the magenta image will be smaller for a color image with a strong magenta tone than for a yellow image and an asian image. , a reproduced color image with a well-balanced color tone in which the strong magenta tone of the original image is suppressed can be obtained. At the same time, it is also possible to correct variations in the sensitivity characteristics of a solid-state imaging device, that is, a photoreceptor such as a COD, for each wavelength of light. As mentioned above, by appropriately selecting the preset value of the counter/g for each primary color R, G, and B using the sequence controller/g, it is possible to easily adjust the tone of the reproduced color image. It is possible to easily correct variations in sensitivity of a photoreceptor when printing a reproduced color image.

Note that in the configuration example described above, a single oscillator l
The sampling point for each pixel was set by dividing the oscillation output of //J, //J, by providing multiple oscillators with different oscillation frequencies.
//'I...Unlike the barrel branching relationship, even if different sampling values are selected continuously, the same effect as described above can be obtained. It should be noted that the dither circuit// and buffer memory/2 in the configuration example shown in FIG. 3 can provide the same effects as those of the conventional device described above with reference to FIG.

As is clear from the above description, according to the present invention, the color balance of a color image reproduced by a matrix arrangement of pixels based on image data from a solid-state image sensor in the order of image reading is determined for each color by the pixel interval in the matrix arrangement. By simple signal processing of making the values different, a special effect can be obtained in that a reproduced color image with good colors can be obtained through easy and accurate adjustment.

[Brief explanation of drawings]

FIG. 1 is a layout diagram showing the general structure of a conventional image reading device, FIG. 2 is a block diagram showing the detailed structure thereof, and FIG. 3 is a block diagram showing an example of the structure of the image reading device of the present invention. Figures (4) and (B) are waveforms sequentially showing examples of the Sarapring Ray)ff constant mode, Figure 5 is a diagram showing an example of the sampling mode, and Figure 6 is a diagram showing examples of the sampling mode. FIG. 3 is a block diagram showing an example of the configuration of the timing control circuit α. l...mouth lamp, c...image, 3...mirror, l...lens, j...color separation filter, 6...COD. 7... - body reading element, za... oscillator, 9... level shift circuit, 10... analog-digital converter, //... dither circuit, /2... buffer memory, / 3... Gate, /l... Sequence controller, /j... Timer control circuit, 74, 7g... Counter, /7, /9... Preset circuit, 〃, 2/...
Flip-flop, n...and gate. Patent applicant Canon Co., Ltd. agent Patent attorney Tani - Figure 3-4 Figure 4 Figure 5 ↓

Claims (1)

[Claims] In an image reading device that includes a color separation filter and a solid-state image sensor, and reads out image data obtained by performing multiple line scans for each different color by the solid-state image sensor via the color separation filter for each successive line scan. , an image reading device characterized in that the line scanning interval is made different for each different color.