JPS6153870A - Light source lighting up method of picture reader - Google Patents

Abstract

PURPOSE:To simplify a circuit constitution and to accelerate a processing by setting light source light having a white color and the one suitable to the reading of an original and making the light incident on the original so as to read it. CONSTITUTION:Three color fluorescent lamps 7-9 are used as a light source incident on an original. In accordance with the drop-out color mode of an arbitrary color or black/white mode, the combination of off/on timing of said fluorescent lamps 7-9 are changed, and the incident light is caused to be in a black/ white mode or drop-out color mode at the time of CCD1 incident light. Consequently the synthesization of dissolved colors and the discrimination of the picture which is read out strongly and of the color which is not read out and remains white can be carried out by colors of the light source incident on the original.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method of lighting a light source of an image reading device, and more particularly to a method of controlling the lighting timing of an image reading device using a three-color fluorescent lamp as a light source.

<Prior art and its drawbacks> Conventional color reading devices have a configuration in which a single white light source is irradiated onto a document, and the reflected light is separated into three primary colors and read by three CCDs. The main device has a configuration in which the light reflected from the document is sequentially AIMed through the three color filters and then incident on the CCD.

If these devices are to perform black-and-white reading, the original must be read in color, and then the color-separated data must be combined using an electric circuit.

However, if the above synthesis was attempted to be performed using a ROM, a large-capacity ROM or an adder circuit would be required, and if attempted to be performed using a CPU, the conversion would take a long time and the reading speed would be slow.

In addition, if you want to change the balance between the color data you want to emphasize and the color data you want to erase by whitening out of the color-separated data, and then combine them into black and white data, it becomes more complicated and larger than the above-mentioned equipment.

<Object of the Invention> In view of the above-mentioned drawbacks, the present invention provides an image reading device that realizes clear reading in monochrome mode and dropout color mode in addition to normal color reading of color originals by installing a minimum amount of ROM. The purpose is to provide

<Configuration of the Invention> To summarize, the present invention uses three-color fluorescent lamps in an image reading device, and turns on and off the three-color fluorescent lamps according to a black-and-white mode or a dropout color mode of any color. It is characterized by changing the combination of timings, such as turning on the red fluorescent lamp and blue fluorescent lamp at the same time while the green fluorescent lamp is turned off, or turning on all three fluorescent lamps at the same time. By doing so, the incident light is already set to the black and white mode or the color mode to Drosopau 1 when the light enters the CCD.

<Embodiment> FIG. 4 is a schematic structural diagram of an optical system of an image reading apparatus that implements the method of the present invention. Three colors (red, green.

Blue) fluorescent light7. 8. 9 is installed at approximately the same distance from the reading line (scan & S) set on the original 11, and irradiates this reading line. Reflector 12. The lens 13 is installed at a position where the reflected light reflected by the reading line 2 enters the CCD 1. The CCD 1 has n elements and reads the density on the reading line of the original as analog data. The original 11 is scanned from left to right in the figure.

FIG. 3 is a block diagram of the image reading device. CCD
II, n analog data detected by n elements are A
/D converter 2.

A/D converter 2 converts each data into m-bit digital data and transmits it to memory 3 or memory 3'. Memory 3.3' stores the input digital data as R.
Enter into OM4. Here, the memories 3 and 3' have similar configurations, but when one memory is writing data from the A/D converter 2, the other memory Data is being output (read) to. This is to increase the speed of image reading by simultaneously performing input from the A/D controller 2 and output to the ROM 4. Cl) U 5 is this R
A read switching signal Ad is output to OM4. When this read switching signal Ad is “1”, the ROM
4 is data input from memory 3, 3' (8 of 2'''
The input data is converted into white and black binary values and output, and when the read switching signal Ad is "0", the input data is output as is.

The CPU 5 outputs a read/write signal R/W instructing writing or reading to the memory 3.3', and
These write and read addresses are output via an address bus.

Since this image reading device is also used as a color reading device, the memories 3.3' are red signal memories 3R, 3'R, green signal memories 3G, 3'G, and blue signal memories 3B, 3. 'B. The CPU 5 outputs memory select signals S, , s2 to the memories 3, 3' to designate the memory to be used. The memory select signals S+ and S2 are each 1 bit "'1".
, '0' signal. When St and Sz are "o" and "o", specify red signal memories 3R and 3'R, and
When S2 is "1" or "0", green signal memory 3G or 3'G is specified, and S2 is "'0" or "
1'', the blue signal memories 3B and 3'B are designated.The CPU 5 sequentially repeats the above designations.

Further, this CPU 5 sends a red fluorescent lamp lighting signal RFLO to a lighting circuit 6 that controls blinking of the three-color fluorescent lamps 7, 8, and 9.
N, green fluorescent lamp lighting signal G F L ON, blue fluorescent lamp lighting signal B F 1. , ON is output. When the lighting signal becomes "P1", the lighting circuit 6 lights the fluorescent lamp corresponding to the signal.

Here, the fluorescent lights 7.8.9 irradiate the document with all three lights, a combination of two lights, or one light alone, and in each case, the color of the irradiated light varies. are different. FIG. 2 shows a table of the colors of the irradiated light synthesized by the lit fluorescent lamps. When three fluorescent lamps are turned on, the irradiation light becomes substantially white light, so that reading is performed according to the black and white density of the document. Reading using the above lighting method is called reading using black and white mode.

When two or one fluorescent lamp is turned on, the emitted light has a certain color. Therefore, in reading, the reading density is determined by the relationship between the color of the image and the color of the light source as well as the density of the image. If the image has a color similar to that of the light source, the image will be read at a lower density than its original density, and if the image has a color similar to the complementary color of the light source, the image will be read at its original density. It can be read more deeply.

Reading using the lighting method described above is called reading using the dropout color mode of the color of the irradiated light.''The timing chart of the fluorescent lamp lighting signal and CCD output when reading a document using the characteristics mentioned above is shown in Figure 1. Diagram (A
), (B), and (C). FIG. 5A shows the case of reading in the red dropout color mode. Only a red fluorescent light is turned on as a light source for illuminating the original. Therefore, in the image of the document, the red part is hardly read and remains white, and the blue and green light images are read darkly. FIG. 6B shows the case of reading in cyan dropout color mode. As a light source that illuminates the original,
Green and blue fluorescent lights are lit. Therefore, the light source has a cyan color. Therefore, the green and blue portions of the original image are hardly read and remain white, while the red image is read together. The reading shown in Figure (8) is, for example,
It is effective when used to read a document in which a black or blue image is recorded on red paper. This method is effective when used when reading a document in which information is recorded. FIG. 6C shows the case of reading in black and white mode. Since all three fluorescent lights are on, the one light from the previous year is almost white. Therefore, the document is read approximately based on the density of the image. In addition, (D) in the same figure shows the fluorescent lamp lighting signal and C when performing color reading by sequentially lighting three colored fluorescent lamps.
The timing chart for CD output is shown for reference.

As mentioned above, if you estimate the light that illuminates the original, set it to a color suitable for black-and-white reading, and read the document, the only hardware required is a ROM for black-and-white binary conversion. Therefore, it is possible to combine separated colors and identify images that are too dark to be read and images that are unreadable and want to remain white.
When the ROM is used, the circuit configuration can be much simpler than when the ROM and the adder circuit are used. Furthermore, the processing speed is faster than when the CPU is used for calculations.

<Effects of the Invention> As described above, according to the present invention, the light source light having white and a color suitable for reading the original is set, and the original is read by irradiating the light, so that the separated colors are The color of the light source that irradiates the document can be used to synthesize images and identify images that are to be read darkly and images that are not to be read and are to be left white. Since the read data has already been identified as described above, subsequent processing may be analog/digital conversion and black/white binary conversion. Therefore, the circuit configuration is much simpler than when the discrimination is performed using a ROM or a ROM and an adder circuit, and the processing speed is also faster than when the distinction is performed using a CPU.

[Brief explanation of the drawing]

Fig. 1 (A), (B), (C) Fluorescent lamp lighting signal and CCD by the image reading method according to the tobacco invention
An example of an output timing chart is shown. FIG. 5D is a timing chart for color reading. Figure 2 is a diagram showing the relationship between lit fluorescent lamps and composite colors;
The figure is a block diagram of an example of an image reading apparatus that implements the method of the present invention, and FIG. 4 is a schematic structural diagram of the optical system of the image reading apparatus. 1-CCD, 2-A/D converter, 3.3'-memory, 4. -ROM, 5-CPU, 6-Lighting circuit, 7.8.9-Fluorescent lamp.

Claims (1)

[Claims] (1) It has three-color fluorescent lamps of red, blue, and green and a CCD sensor, and the document is irradiated with light from the three-color fluorescent lamps, and the CCD sensor reads the reflected light. The image reading device that reads an image of the original document is characterized in that the combination of on/off timings of the three-color fluorescent lamps is changed according to a black and white mode or a dropout color mode of an arbitrary color. How to turn on the light source.