JPS60116273A - Color picture reader - Google Patents

Abstract

PURPOSE:To process data by a signal processing circuit by making each integration period of image sensors arranged in series on a line identical. CONSTITUTION:A shift signal SFT is fed to a shift terminal of the image sensors IS1, IS2 and also fed to a J terminal of an FF1 and a K terminal of an FF2. Moreover, a clock CLK is fed to a CK terminal of the FFs 1, 2 and AND gates AND1, AND2. A Q output of the FF1, LFF2 is fed to other inputs of the AND1 and AND2. Then the output of the AND gates AND1, AND2 is fed to the clock terminal of the image sensors IS1, IS2 so as to read a data from the image sensors IS1, 2. Through the constitution above, the integration period of each image sensor is made identical. Thus, the data is processed by one signal processing circuit.

Description

[Detailed Description of the Invention] (Field of Application) The present invention relates to a color image reading device.
In particular, the present invention relates to a color image reading device in which a plurality of COD image sensors are arranged in series in a straight line to read one line of images.

(Conventional technology For full-color image @reading, a document is sequentially and periodically irradiated with a light source of 40 different tones, and the intensity of reflected light from the document due to each color dimming is measured individually for each pixel using an image sensor. Conventionally, a color signal for each pixel is calculated by detecting the color and performing image processing based on the detection.

In addition, if an image sensor with large dimensions and the required length cannot be obtained, as shown in FIG. L1.
L2 is used to divide and form images on image sensors 131 and 182 provided in correspondence with each other. Obtaining a signal is being carried out.

At that time, image processing (
For example, if an attempt is made to perform the calculation of color signals using processing circuits corresponding to each color tone, the processing circuits will be required in duplicate, resulting in a complicated structure and a disadvantage of high loss.

As a solution to this problem, it has been considered to provide only one image processing circuit common to all image sensors, and to perform Bi removal for each image sensor with a time shift.

In this case, the control connection of the image sensor section is shown in Figure 2.
An example of the operation timing chart of the motor is shown in Fig. 3.

Note that here, it is assumed that a COD image sensor is used as the image sensor.

As is well known, a COD image sensor includes a large number of photodiodes that generate charges in each pixel according to the intensity of irradiated light, a storage electrode that accumulates the charge for each pixel, and a temporary memory for the storage electrode. and a shift gate that controls charge transfer from the storage = two poles to the corresponding shift register.

By supplying a read clock to the shift register, electrical analog signals for each pixel are serially and sequentially output. Therefore, in the COD image sensor, the image information integration period is equal to the period of the shift pulse applied to the shift signal 1-.

The waveforms (A) and (B) in FIG. 3 are the timing of the document OD pre-irradiation with red light and blue light, respectively. As is clear from the figure, the original OD is alternately irradiated with red light and blue light.

The shift/readout-start signal @RST for the image sensor JSI is generated, for example, at the same 11JJ timing as the lighting start Un d3 and the disappearance timing of each color light source, as shown in FIG. 3(C). Image sensor IS1
The transfer of the accumulated charge stored in each COD image register to the shift register, and the start timing for reading from the shift register are determined.

On the other hand, the shift/readout start signal R8T for the image sensor 182 is as shown in FIG. 3(E).
It is generated in response to a reading end signal EO8 from the image sensor 181.

The image sensor 182 is activated by the reading end signal EO8.
Transfer of accumulated charges in each COD image sensor to the shift register and reading from the shift register are started.

In operation, as shown in FIG. 3, red light irradiation (R
1) is completed, and blue light irradiation (B1) is started. At the same time, as can be seen from FIG. 2, the shift/read start signal R8T-1 is also supplied to the image sensor IS1.

As a result, in the image sensor ISI, the accumulated charge of the COD image sensor is transferred to the shift register, and at the same time, reading of the shift register is started by the clock CLK. The read signal is output as a serial signal to output terminals 0-1.

When the reading of image sensor 9-IS1 is completed,
As shown in FIG. 3(E), a reading end signal EO8 is generated from the image sensor ISI, and this signal causes the accumulated charge of the image sensor IS2 to be transferred to the shift register as shown by the waveform (F) in FIG. The reading is started and a read signal is output to the output terminals 0-2.

In synchronization with the completion of reading by the image sensor 182, the next shift/read start signal R8T-2 is generated, and the same reading operation as described above is performed.

Note that reading by the image sensor 182 does not have to be started with the reading end signal EO8, but can also be started with the shift/continue start signal R8T.

At this time, the signal integration time of each CCD element in the image sensor 181 becomes as shown by reference numeral 11 in FIG. Therefore, no problem arises.

However, when looking at each CCD element within the image sensor 182, its signal integration time becomes as shown by reference numeral I2 in FIG. 3, and extends over lighting periods of different color tones. Therefore, the read output signal from the image sensor IS2 cannot be matched with the output signal from the image sensor ISI, and there is a drawback that a correct color signal cannot be obtained for each pixel.

(Objective) The present invention has been made to eliminate the above-mentioned drawbacks, and its object is to solve the problem of a certain color even when a plurality of image sensors and a common image processing circuit are used. The object of the present invention is to provide a color image reading device capable of photoelectrically converting information in an integral interval within a lighting period of an irradiation light source.

(Summary) In order to achieve the above object, the present invention provides a system in which the timing for transferring the accumulated charge of the image sensor CCD in the image sensors 181 and [82 to the shift register is set at the timing of transferring the accumulated charge of the image sensor CCD in the image sensors 181 and 82 to the shift register of the image sensors connected in series. The feature is that all the readings are performed at the same time, and only the timing of the start of reading is sequentially shifted in time.

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

FIGS. 4 and 5 are block diagrams of essential parts and timing charts of an embodiment of the present invention. In these figures, the same reference numerals as in FIGS. 2 and 3 represent the same or equivalent parts.

The shift signal SFT is applied to the image sensors υIS1 and 18.
The J terminal of the first flip-flop FF1 and the second flip-flop FF2 are supplied to the shift terminal of the second flip-flop FF1.
is supplied to the terminal.

CK terminal of FF2 and AND gate AND1゜AND
2. The other inputs of the AND gates AND1 and AND2 are supplied with the Q outputs of the first flip-flop FF1 and the second flip-flop FF2, respectively.

AND GO 1 - The outputs of AN D 1 and AND2 are sent to each image sensor vIS1. It is supplied to the clock terminal of IS2 and functions to read data from the image sensor 13.

In operation, as can be seen from FIG. 5, when shift signal 5FT-1 is generated in response to turning off the red light source and turning on the blue light source (FIG. 5C), image sensor 151. IS
The two accumulated charges are transferred to the corresponding shift registers and temporarily stored.

On the other hand, the first flip-flop FF1 is set and the second flip-flop FF2 is reset by the shift signal 5ET-1.

The Q output power of the 17th lip-flop FF1 (becomes "1", so the AND gate A N D 1 b' Ittl
71)
It is input to the clock terminal of S1. By doing this, the same figure (
As shown in D), signals are read from the shift register of the image sensor IS1.

When the reading of the image sensor IS1 is completed, a reading end signal EO3 is generated and is applied to the two flip-flops, so that the 171st flip-flop FF1
is reset, and the second flip-flop FF2 enters the cellar 1~ state. Therefore, the ant gate AND1 is closed, and on the contrary, the ant gate AND1 and AND2 are opened.

The clock CLK is supplied to the image sensor IS2 via the analog game j to AND2, and as shown in FIG.
A signal is read from the shift l-register of the image sensor IS2.

After the signal reading from the image sensor 182 is completed, the shift 1-signal 5ET-2 is generated at a predetermined timing, and the above-described operation is repeated.

As is clear from the above description, according to this embodiment,
Two image sensors IS1. The charges accumulated in IS2 are transferred to the shift register at the same timing, so
It is possible to make both integration periods equal, and therefore, it is possible to make this integration period fall within the lighting period of the same color adjustment light source.

In the example shown in FIG. 4, the reading end signal EO3 of the image sensor IS1 is used to control the reading start timing of the image sensor 182, but instead, the reading start timing of the image sensor 182 can be controlled by using an appropriate means (for example, a timer). It is clear that a second read start signal may also be used which has a predetermined time delay with respect to the shift/signal SFT.

Further, although the example shown in FIG. 4 is an example in which two image sensors are connected in series, the present invention can be similarly applied to a case in which three or more image sensors are connected in series.

FIG. 6 is a block diagram of another embodiment of the present invention, and 3j
This is an example in which fJA image sensors are connected in series, all image sensors are shifted at the same timing, and read out is sequentially performed with a temporal shift.

The operation of this embodiment will be easily understood without further explanation.

Although only an example using a COD image sensor has been described above, even when using an image sensor having a normal electric charge storage means, a shift register and a shift register for temporarily storing the accumulated charge of each pixel can be used. , and charge transfer control means to this shift register.
It goes without saying that the invention can be applied in exactly the same way.

(Effects) As is clear from X++ 1111 of LJ, l-, according to the present invention, the following effects are achieved.

(1) The integration period of all image sensors can be made the same, and therefore, this integration period can be made to fall within the lighting period of the same color-adjustable light source. This allows outputs from all image sensors to be processed by one common signal processing circuit.

(2) As a result of (1) above, the configuration of the signal processing circuit can be simplified and costs can be reduced, and furthermore, reliability can be improved and errors caused by variations in the characteristics of the signal processing circuit can be eliminated. can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a color image reading device to which the present invention is applied, and FIG. 2 is a block diagram of the main parts of the conventional color image reading device illustrating image sensor control.
3 is a timing chart for explaining the operation of FIG. 2, FIG. 4 is a block diagram of the main part for explaining the image sensor control of the present invention, and FIG. 5 is for explaining the operation of FIG. 4. FIG. 6 is a main part block diagram for explaining image sensor control according to another embodiment of the present invention. OD...Original, Ll, L2...Imaging lens system, IS
1 to 183...Image sensor, CLK...Clock, R8T...Shift 1~/reading start signal, EO
8...reading end signal, SFT...shift signal Patent attorney Michito Hiraki 18 Fig. 1 rI Fig. 2 Fig. 4 Fig. 5

Claims (2)

[Claims] (1) A plurality of light sources that generate light of different tones and are arranged to illuminate the same reading area of the original to be read, means for controlling the light emission timing of the light sources, and an image sensor that converts the reflected light intensity of the image into an electrical analog signal for each pixel, an optical means that forms an image of the reading area of the document on the image sensor, and irradiation of each pixel by a light source of each color tone. In the color image reading device, the image sensor includes a means for calculating and outputting a color signal of the pixel based on a plurality of electrical signals obtained from the image sensor. The electric charges stored in each of the plurality of image sensors are arranged in series to correspond to one line, and the electric charges stored in each of the plurality of image sensors are connected to the plurality of shift registers.
1. A color image reading device comprising: means for transferring signals from each shift register to Mj; and means for sequentially outputting signals from each shift register to Mj. (2) The color image reading device according to claim 1, wherein the image sensor is a COD image sensor.