JPS59194568A - Picture reader - Google Patents

Abstract

PURPOSE:To obtain a clear picture prevented from being blurred to the outside of the outline of the picture and an out-of-focus image by using three control signals outputted in accordance with the size of a Y signal. CONSTITUTION:A pair of CCD sensors out of three pairs obtain a reading signal without color decomposition and other two pairs obtain reading signals after decomposing a color into two different colors. When a decision circuit 32 decides the size of the Y signal as the 1st ash level, G, R and B signals outputted from operational amplifiers 31, 29, 30 are respectively outputted to terminals 34G, 34R, 34B. When the decision circuit 32 decides the size of the Y signal as the 2nd white level, previously fixed decomposition colors of the white level is sent from reference signal generating circuits 35G, 35R, 35B. When the decision circuit 32 decides the size of the Y signal as the 3rd black level, ''0'' level outputs are sent from reference signal generating circuits 36G, 36R, 36B. Thus, a color blur to other parts can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an image reading device used in a facsimile machine, etc., and is particularly capable of clearly reading the contours of characters, figures, etc. written in different colors. Regarding the reading device that can be used.

(b) Conventional technology and problems A conventional example will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram of the image reading device, and the diagram shows the principle;
(B) shows the positional shift of the CCDIJ near sensor, and (C) shows the color blurring of the image.

In the figure, l is a screen to be read, which is continuously moved in the direction of the arrow by a paper feed mechanism (not shown). 2, 3.
4 is filled with red, green, and blue (hereinafter abbreviated as R, G, and B, respectively), and 5°6.7 is filled with R, G, and blue, respectively.
The imaging lens B, 8°9.10, is a CCDIJ near sensor that converts R, G, and B image information into electrical signals, respectively. Further, 11 indicates the position of the line being read. This method has the disadvantage that unless the three optical systems accurately read the same position on the line 11, not only the color but also the outline of the image will be read incorrectly. .

(13) is an explanatory diagram showing the reading area of each CCDIJCCD linear sensor +1 (line 11),
For example, if the reading position is shifted and the R CCD reads area 12,
If the G CCD captures area 13 and the B CCD captures area 14, the output figure will be 15 if the document is black and a square with 141 written in it (C).
is 16. B is read as 17. Therefore, the figure that is correctly determined to be black is 15. lf), 17 are cross-hatched areas that overlap at the same time, and other areas have the drawback of color bleeding.

FIG. 2 shows a principle diagram of an optical system suitable for implementing the present invention. In the figure, 18 is a reading position, and 19 is a slit 7 that eliminates interference of incident light from sources other than the reading section.

2() is a triple image filter using an obtuse prism, and (
■3) Appearance as shown in the figure) It is a #1Q prism. 21 is a projection lens, and 22 to 24 are filters for desired color separation.

CCD linear sensors 25 to 27 each read the color-separated light. This configuration only requires one lens, but three
Image formation by two CCD'j CCD linear sensors still requires positional adjustment, and the same drawbacks as in the case of FIG. 1 cannot be eliminated. Also, due to the chromatic dispersion of the prism 20, the CCD at both ends
! There is a drawback that the images of the near sensors 25 and 27 are blurred.

(c) Object of the Invention In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide an image reading device that can clearly read the outline of an image.

(d) Structure and object of the invention According to the present invention, in an image reading apparatus that converts reflected light obtained by sweeping the surface to be read of a document into reading signals by three sets of CCD sensors, One set of CCD sensors obtains a read signal without color-separating the reflected light, and the other two sets obtain read signals by color-separating the reflected light into two different colors, and also obtain read signals without color-separating the reflected light. an operational amplifier that outputs a level I signal corresponding to the difference between the two color-separated read signals; a brightness determination circuit that outputs a three-value level I signal based on the brightness of the read signal that is not separated into two colors; and at least one pair of A reference signal generation circuit is provided, I)iI
When the output of the judgment circuit is at the first level, the output of the operational amplifier and the two color-separated read signals are outputted independently, and when the output is at the second level, the output of the pair of Nobuo/Nobuo generation circuits is output. Output one output signal and N 81'! This is achieved by providing a one-time image reading device which outputs the output signal of the other of a pair of reference signal generating circuits when the level is J.

(e) Embodiments of the Invention Examples of the present invention will now be described in detail with reference to the drawings. In the top view, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

Figure 3 shows the image signal processing circuit of the image reading device according to the present invention, which is similar to 11! shown in Figure 1. ! I will explain the case where it is applied to an image reading device. Conventionally, light is composed of a combination of three primary colors of light, and if the combination ratio of light and dark is Y, red is R2, blue is B, and green is G. , Y=R1B+(
It is generally known that , holds true. Using ζ and R in reverse, the three primary colors Shirakawa Reka, for example, green is G=Y-
It can also be synthesized by R-B.

In the color separation system of the image reading apparatus shown in FIG. 1, in order to separate the three systems into Y, R and B, it is only necessary to remove the G filter 3, for example. Actually CCUIJCCD
Since the linear sensor is somewhat sensitive to infrared rays, an ultraviolet and infrared filter unnecessary for reading R+G+B is installed in place of the G filter 3.

As a result, CCD8 is R, CCD9 is Y, and CCD1
0 outputs an image signal corresponding to B.

FIG. 3 shows a color separation and synthesis circuit of an image reading device according to the present invention. In the figure, 28 is the CCD 9, that is, the Y signal amplifier, 29 is the CCD 8's R (= i-th amplifier, 30
is an amplifier for the B signal of c CD 10. .

Each of these amplifiers corrects illumination inequalities for each read signal, and further adjusts the gain so that Y=R+B+G. Reference numeral 31 denotes an operational amplifier which performs the calculation of G=YR-B through the connections shown in the figure to obtain a G signal. Reference numeral 32 denotes a Y signal determination circuit, which outputs the fli control signal 311f (of 311f) corresponding to the magnitude of the Y-signal. For example, when determining the Y signal and determining that it is at its own level, the second level ゛]", when the gray level is the first level) V "0", when the black level is the third level "-"
Let's do it. 33 is a switching circuit (for example, a switching relay), and a switching circuit 33c with three contacts for each system.H3: (R
,! , '3 o are arranged and interlocked. 34c, 34g, and 34B are respectively G (
This is the output terminal for No. i7, R signal, and B signal. , 15G is a reference signal generation circuit that sends out a green component level included in white; 35. is a reference signal generation circuit that sends out the level of the red component included in white.

35+1 sends out the color component level of 1 included in white - J11. l(ra signal generation circuit; +6 G and
31; B and 3tin are the reference light generation paths No. 48 that send out the respective levels of green, red, and -H components included in black, but in reality, they are set to 0 level output so as not to pick up miscellaneous materials. There is only a matching resistor.

However, if the PIJ constant circuit 32 determines that the magnitude of the Y signal is the first level, that is, the gray level, and outputs a control signal of "0", the switching relay 33 will move the contact point to the center in response to this. The output G signal of the operational amplifier 31, the output R signal of the amplifier 29, and the output B signal of the amplifier 3() are outputted to the green, red, and blue output terminals 34G, respectively.

It is output directly to 34R and 34B. Next one judgment circuit 32
Determine the white mark which is the second level 7 of power 5 and get “10l”
If you output the Luri control signal, it will switch accordingly.') Ray 3:3 acts so that the contact point is located on the upper side, and generates reference signals for the predetermined white level separation color at the edge, red, and blue streaks. Circuits 35c, 35R, ,' (sent from 5n, each CCD
It is sent out in place of the read signal. Therefore, the composite output (completely white and clear).Next, the power of the judgment circuit 32 is
The black level, which is the level of , is determined, and fli! of "-1" is determined.
When the Ifl:1 signal is output, the switching relay 33 (1) is switched to the 1 side by the same action, and connected to each contact, the standard A word generation circuit 36a, 3 (i*, 36n C (l level) The output is sent out and the composite output is completely black and clear. Therefore, color bleeding into other Mi parts can be removed. Note that if the I word is +1" and "-1", it is white. It is also possible to output a signal corresponding to a predetermined specific color instead of black.It is also possible to create a specific color on the receiving side by sending a specific signal 91 between the father and son. In the false #6i example, relays were used to explain the switching means to make it easier to understand, but in reality, each j4 (j gate, nuitching half jj', 417 copies were created.

In general, changes in color are gradual compared to changes in brightness, and if the changes in Iwamei 1) 1 and ↑ are correctly reproduced, human jf
It is known that J's 11 feels natural.

In carrying out the present invention, utilizing this 1.]: fact,
The pixel density of CCDs 8 and 10 for reading 1 and B in FIG. 1 can be made smaller than that of CCD 9 for Y. -1
If the circuit shown in Fig. 3 is used for this yA combination, the bright and dark 9 combinations (changes between white and black will maintain the pixel density of the Y signal).
Since this preset-C is set, INIJ 11 is displayed 18
The clarity of 1 can be maintained.

Next, use the circuit shown in Figure 3 in the optical system of 414J'5r, which is transferred to No. 21g1. Read the Y1H number at the 1st position (for example, the CCI of the Koo line) 26 ), and read the Y1H issue at the 1st position 1d of the other two 1st positions (1D) of the Mihara Mihara of Light (
Example 1. If fl < and B) are taken as C, then R and B
The number of pixels read by the prism 20 may be smaller than that of Y.
Even if there is blur due to chromatic dispersion, a clear image can be obtained as in the case described above.

(f+ Effects of the Invention As explained in detail above, according to the present invention, it is possible to obtain an image without color discoloration or blurring outside the outline of the image).
jf function and the +1Iif elementary density of the CCD for color information reading can be reduced, which has the effect of enabling reading with a simpler optical system.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the principle of a conventional image reading device and color misregistration.
FIG. 2 is a principle diagram of an optical system suitable for carrying out the present invention, and FIG. 3 shows an image signal processing circuit of an image reading apparatus M according to the present invention. In the figure, l is a screen, 8 to 10 are CCD linear sensors, 31 is an operator, 32 is a judgment circuit, and 33 is a switching circuit.

Claims (1)

[Scope of Claims] In an image reading device in which reflected light obtained by sweeping a surface to be read of a document is converted into a reading signal by three sets of CCD sensors, one set of the three sets of CCD sensors 11 read signals are obtained without color-separating the light, and the other two groups obtain read signals by color-separating the reflected light into two different colors. An operational amplifier outputs a level corresponding to the difference in signals; a brightness determination circuit outputs a three-value level based on the brightness of a read signal that is not separated into two colors; and at least one pair of reference signal generation circuits; When the output is at the first level, the output of the operational amplifier and 2
The two color-separated reading signals are output independently, and the second
When the third level is I, the output signal of one of the pair of reference signal generation circuits is output, and when the third level is I, the output signal of the other of the pair of reference signal generation circuits is output. Image reading device.