JPH012467A - image reading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention uses a line image sensor consisting of a plurality of line image sensor chips arranged in the main running eclipse direction.
The present invention relates to an image reading device that reads images on a document.

(Prior art) Conventional general line image sensors that use solid-state imaging devices such as CCDs and are called close-contact type (imaging magnification corresponds to the same magnification) have a single chip that can be used in standard formats such as A4 or A3 size. Since it is difficult to realize a long type that can cover the width of the original size, the product is one in which multiple line image sensors are arranged in a staggered pattern in the main scanning direction to form one line image sensor. (e.g. Toshiba gTc
Dl11e.

TCD112C, etc.) g Letay 6゜These products use a staggered arrangement, so spatial and temporal deviations in the sub-scanning direction that occur can be corrected using the built-in analog line memory, and the cost from the sensor can be corrected. The read signals could be processed without being aware of the staggered arrangement.

1g image using this line image sensor! The spherical configuration shown in FIG. 4 can be considered as the U-removal device. This is similar to the embodiment of the present invention shown in FIG. 1, which will be described later, and uses two A-D converters for a line image sensor I having a four-chip configuration, but data selectors lla and Ilb
The combination of read signals input to the data selector l
The read signals of the CCL line sensor chips 2 and 3 are input to la, and the read signals of the CCD line sensor chips 4 and 5 are input to the data selector 11b. This is distributed in order according to the main scanning direction, and has a limited configuration in order to simplify processing in the array circuit 15 later.

However, in recent years, image reading apparatuses have been required to have various functions, and it has become common to have an enlargement@reduction reading function. When realizing this magnification/reduction function, there is no problem when enlarging/reducing a two-dimensional optical image using an imaging lens system, but if a close-contact type imaging lens system such as a self-oak lens is used, the optical Since the imaging magnification is fixed, enlargement/reduction is performed by varying electrical signal processing in the main scanning direction and mechanical feed amount in the sub-scanning direction. Furthermore, when achieving different magnifications in the main scanning direction and the sub-scanning direction, it is necessary to vary the mechanical feed amount in the sub-scanning direction.

When the sampling beach in the sub-scanning direction is mechanically varied in this way, the number of lines in the line memory for misalignment correction must also be varied correspondingly. Especially when enlarging, the number of line memory lines (capacity t) required for misalignment correction
) increases.

However, the analog line memory with a built-in line image sensor is undesirable for signal accuracy deterioration and for structural reasons to further increase the violet, and as a result, there is a limit (up to 2x) in the adaptive magnification range for the enlargement/reduction function.

(Problems to be Solved by the Invention) As described above, in the conventional image reading device using a line image sensor arranged in a staggered manner and having a built-in line memory for misalignment correction, there is a limit to the magnification range and function of the enlargement/reduction function. There was a problem. .

By providing a digital line memory in an external signal processing system, the present invention can expand its magnification range, form a high-speed and efficient correction processing circuit, and can support various enlargement/reduction functions. ! The purpose is to provide a reading device.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a λ-reconverter for digitizing an analog read signal from a line image sensor formed by arranging line image sensor chips in a staggered manner, and an A-to-D converter for this Analog or digital signals before and after the device are divided into read signals of the line image sensor chip group that require misalignment correction and read signals of the line image sensor chip group that do not require misalignment correction, and each signal is separated into a separate system. The present invention is characterized in that a signal processing system that constitutes a processing system and that requires deviation correction is provided with a digital line memory for deviation correction, the number of lines as required.

(Function) In the present invention, the required number of correction lines (memory capacity) is determined from the sampling pitch variable range in the sub-scanning direction and the amount of deviation in the sub-scanning direction of the line image sensor chips arranged in a staggered manner. If the number of correction lines is insufficient for the analog line memory built into the line image sensor, the adaptive magnification can be increased by adopting a configuration that allows the correction line memory to be placed externally. In addition, the number of line memories can be freely increased or decreased in accordance with various requirements, and correction can always be performed efficiently with the optimum number of line memories.

In addition, by separating the signal processing system that requires misalignment correction from the signal processing system that does not require misalignment correction, misalignment correction processing can be performed efficiently.Furthermore, digital line memo IJ and P can be used as external correction memory. By doing so, it is possible to realize correction without deteriorating the accuracy of the thread removal signal.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram of a signal processing system of an image reading device fi according to an embodiment of the present invention.

In this embodiment, the line image sensor 1 has one pixel 62.
C with 1024 pixels of photosensitive area of 5 x 62.5 μm size
OD line image sensor chive 2, 3, 4.5 1,000
It is arranged in a shape. According to this line image sensor 11, if the magnification of the imaging optical system is 1x, 5lIB4 version (2
It is possible to read an image on a document with a width of 56 mm (width) at a resolution of 16 do/h/mm. In addition, since there is a DR gap (n times the reading pitch) in the sub-scanning direction due to the staggered arrangement, each of the CclD line image sensor chips 2 and 4 is provided with an analog line memory 6.7 for correction. It is being (DR in Figure 1.

= 250 μm 1 The number of lines Jt of the analog line memory for correction is 4 lines each. ) The line image sensor 1 is activated by the CCD due to the chroma from the chroma generator 8.
It is driven via a driver 9 and outputs an electrical signal corresponding to the read image.

This output signal is passed through the amplifier group 10 to the data selector l.
la, llb are input. At this time, data selector l
The read signal of the CCD line image sensor 2.4 is input to la, and the data selector 11b is input with CO
Read signals from the D-line image sensor chips 3 and 5 are input. The data selector 1la11b is an analog data selector.

As a result, the data selector 1la is supplied with a read signal that requires the same voltage deviation, and the data selector x1bt is supplied with a read signal that does not require deviation correction.

Read signals from data selectors lla and llb are input to A-D converters 12a and 12b, respectively, and converted into digital signals. For example, an 8-bit converter is suitable for the A-D converters 12a and 12b. The digitally converted read signal 13a is further corrected for deviation as necessary using 2048 bytes per line of the delayed digital line memory 14, and is inputted to the array circuit 15ζ. The thread removal signal 13a, which does not require deviation correction, is input as is to the array circuit 15Iζ.

The array circuit 15 outputs one line of time-series signals along the main eclipse direction as arrays Tll, Ftu image signals. The control circuit 16 controls this series of processing, and for misalignment correction, it uses a built-in analog line memory 6.7 in the line image sensor l and an external delay digital line memory 14 according to the number of correction lines required. The number of delay lines is set in each case.

FIG. 2 shows another embodiment of the present invention, in which as many A-Df detectors as there are line image sensors are used. Analog signals from line image sensor chips 2, 3, 4.5 are sent to A-D converters 2)a2)b, 2)C
, 2) (I), and the read signals that require deviation correction are supplied to the data selector 22a, and the read signals that do not require deviation correction are supplied to the data selector 22b.The data selectors 22a and 22b are It is a digital data selector.

The read signal 132c from the data selector 22a is subjected to deviation correction by the delayed digital memory 14. Since deviation correction is necessary, the read signal 132c is inputted to the output 1j circuit 15 together with the thread increase signal 13b, and output as a 1-line image signal. be done.

FIG. 3 shows another embodiment of the present invention, in which a read signal that requires deviation correction and a read signal that does not require deviation correction are processed without being systematized, and the conventional example shown in FIG. This configuration takes advantage of the combination of a line image sensor l and an A-D converter.

'43 jc8, A-Df converter 12a, 12b) Outputs 13a, 13b are multiplexed with signals that require deviation correction and signals that do not require deviation correction, therefore, each processing system I, Delay digital memory 323°32b
C, 1024 bytes per line) and data selectors 31a, 3'lb, 33a, 3 for their input and output, respectively.
3b, signals that require deviation correction are selected to the delay memory side, and signals that do not require deviation correction are selected directly to the array circuit. As a result, it is possible to have the same function as the embodiment according to the present invention shown in FIGS. 1 and 2. However, Figure 1,
It cannot be denied that the circuit configuration is more complicated than the embodiment according to the present invention shown in FIG.

In this way, processing the read signal processing system that requires misalignment correction and the read signal processing system that does not require misalignment correction in separate systems is efficient because it simplifies the circuit configuration and control related to correction line memory control. Misalignment correction can be realized. The arrangement circuit 15 shown in FIGS. 1 and 2 has almost the same circuit configuration as the arrangement circuit 15 shown in FIGS. 3 and 4, except that address generation is slightly improved.

Note that the present invention can be implemented with various modifications without departing from the gist, and in particular, the combinations thereof may be modified depending on the number of line image sensor chips and the number of A-D converters constituting the line image sensor. It is not necessarily limited. In addition to the CCD line image sensor, a BBD line image sensor or an amorphous millicon sensor may be used as the image sensor, and basically any line sensor consisting of multiple chips arranged in a staggered manner can be used. Receive adaptation of the invention.

Furthermore, the present invention can be applied to a staggered line image sensor that does not have an internal line memory for correcting deviation, but only with an external digital line memory for correcting deviation. Also, it can be implemented with a color line image sensor without any problems.

〔Effect of the invention〕

According to the present invention, by providing a digital line memory for misalignment correction as necessary outside the line image sensor, the sampling pitch in the sub-scanning direction can be improved.

The misalignment correction circuit can be configured with a line memory that always has the optimal capacity for the variation of the shift, and the signal processing system that requires rough misalignment correction and the signal processing system that does not need misalignment correction are separated into separate systems. The circuit configuration and control related to line memory control can be simplified. Furthermore, by using digital memory, it is possible to correct the signal without reducing its accuracy. This makes it possible to realize a low-cost image reading device that can meet various requirements, such as a range of magnifications for enlargement and reduction, and independent magnification changes for main scanning and sub-scanning.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a signal processing configuration of an image reading device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention, showing the number of line image sensor chips and A-D conversion. FIG. 3 is a block diagram showing the configuration of signal processing when the number of sensors is equalized. In another embodiment of the present invention, read signals that require misalignment correction and read signals that do not need misalignment correction are processed without being separated. FIG. 4 is a block diagram showing the configuration of conventional signal processing. 2.3,4,5...CCD line image sensor, 1
1a, Ilb・7 analog data selector, 12a, 12
b...A-D converter, 14...Delay digital line memory.

Claims (3)

[Claims] (1) A line image sensor consisting of a line image sensor chip consisting of a plurality of photoelectric conversion elements arranged in a line arranged in a staggered manner in the main scanning direction, and an image formed by forming an image on the line image sensor. In an image reading device, correction processing for the spatial and temporal deviation in the sub-scanning direction that occurs due to the staggered arrangement of the line image sensors is carried out between a group of line image sensor chips that require correction and a group of line image sensor chips that do not require correction. An image reading device characterized in that it is divided into a group of image sensor chips and processes signals in separate systems for each group. (2) The image reading device according to claim 1, wherein the correction processing is performed using a digital signal after AD conversion, and a digital memory is used as the correction line memory. (3) The line image sensor uses a built-in analog line memory that corrects spatial and temporal deviations in the sub-scanning direction caused by the staggered arrangement, and also includes an external signal processing system. 3. The image reading device according to claim 2, further comprising a digital line memory for correcting deviations, thereby making it possible to perform deviation correction processing using both the analog line memory and the digital line memory.