JPS5919465A - Information reader - Google Patents

Abstract

PURPOSE:To make the shading correction easy, by replacing an output corresponding to a marker section with an output from a section other than the marker section among outputs with a reference optical characteristics section read at an image pickup element. CONSTITUTION:The reference optical characteristics section 3 for shading, correction providing the marker section 4 for the joint processing of two image pickup element outputs of plural image pickup elements CCD1, CCD2 arranged in the main scanning direction and a means (RAM)(latch circuit) replacing the output corresponding to the marker section among the outputs with the reference optical characteristics section with an output from a section other than the marker section, are provided. Further, the shading correction is attained by avoiding the effect of the marker section provided for the joint processing of the outputs of the plural image pickup elements. Then, the shading correction is attained without requiring a complicated moving control of the light source device with a simple constitution.

Description

[Detailed Description of the Invention] The present invention relates to an information reading device, which has a simple configuration, and
The subject is a means to perform shading correction.

Regarding conventional technology, in information reading devices used in digital copiers, facsimile machines, etc., an original on which images or characters are displayed is illuminated by a rod-shaped light source, and the reflected light from the original is received by a solid-state image sensor through an imaging lens. Converts original information into electrical signals. In this type of device, the light distribution characteristics of the light source are not uniform, the reflective mirror is dirty, and the brightness of the lens approaches the periphery, resulting in the so-called aos'θ characteristic (where θ indicates the half angle of view of the lens). ), and it is necessary to correct the shading characteristics caused by variations in sensitivity between pits of the image sensor. As a means for this purpose, it has been proposed to perform shading correction using a signal received from reflected light when a white plate is irradiated, which should be the standard for shading correction.

Furthermore, in the above-mentioned information reading device, it has been proposed to arrange a plurality of image sensors side by side in the scanning direction in order to increase resolution and transfer speed. In this case, it is necessary to prevent optical discontinuities from occurring at the boundaries of the areas scanned by each image sensor, and for this purpose, areas are provided that are scanned overlappingly by multiple image sensors.
It has been proposed to arrange a reference marker here and to connect the outputs of a plurality of image sensors using signals read from the reference marker.

When applying these means to an actual information reading device, it is desirable that these two means be incorporated into the device with a simple configuration without interfering with each other.

Purpose of the Invention Accordingly, the present invention provides an information reading device having a shading correction means and a connection processing means for the outputs of a plurality of image sensors, which has a simple configuration and does not require precise positional control of a light source device. It is an object of the present invention to provide a device that can avoid the influence of a marker section provided for connecting the outputs of a plurality of image sensors during shading correction.

Structure of the Invention The present invention has a plurality of image sensors arranged side by side in the main scanning direction (for example, solid-state image sensors 00Dl and 0OD2 in FIG. 1 in the specific example described later): For connection processing of the outputs of the image sensors. A reference optical characteristic section for shading correction (marker section 4 in FIG. 1) provided with a marker section (marker section 4 in FIG. 1)
Similarly, with the reference optical characteristic section 3) in FIG. 1: means for performing shading correction by replacing the output corresponding to the marker section during the output by the reference optical characteristic section read by the image sensor with the output from other than this marker section. (Means for writing the digital value held by the latch circuit 37 in FIG. 2 into the random access memory 33);

In the above, the reference to specific examples shown in the drawings to be described later does not limit the scope of the present invention, and the present invention can be modified as appropriate within the scope of the claims.

In addition, the information read by the reading device of the present invention includes information contained in documents, photographs, maps, or diagrams on which characters, symbols, etc. are displayed, as well as information contained in flat objects such as textile fabrics or textile products. Contains information such as the pattern.

Hereinafter, in this specification, these information carriers will simply be referred to as manuscripts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An information reading device embodying the present invention will be described in detail below with reference to the drawings, including its optical configuration, a specific example of a shading correction section, and the order of processing for linking outputs of a plurality of image sensors.

Regarding the optical configuration of an information reading device that embodies the present invention (Fig. 1) Fig. 1 (A) is a side view showing the optical configuration of an information reading device that embodies the present invention, (Figure CB) is also a plan view. In these figures, l indicates a document mounting table, and 2 indicates its main scanning area. Reference numeral 3 denotes a reference optical characteristic section, which is fixedly or movably arranged with respect to the mounting table l, or placed at a predetermined position thereof. In this specification, with respect to the reference optical characteristic section 3 and the marker section 4 described later, these means are collectively referred to as arrangement. In this example, the reference optical characteristic section 3 has a white plate at a portion that comes into contact with the mounting table 1.

The position of the reference optical characteristic section 3 corresponds to the home position 25 of the light source device 5 (the position when this device is in a resting state). The reference optical characteristic section 3 has characteristics such as color 2, reflectance 2, surface smoothness, etc. that do not affect reflected light and serve as a reference for shading correction. Reference numeral 4 denotes a marker section provided in the reference optical characteristic section 3, and the reflected light when the marker section 4 is irradiated onto the light source device 5 provides a signal for connection processing to be described later. In this example, the marker portion 4 has a thin black line in the portion that comes into contact with the mounting table IK.

Further, the marker section 4 is provided at a portion that is scanned overlappingly by two adjacent optical systems including lenses 10 and 11, respectively.

Reference numeral 5 denotes a light source device, which includes bar-shaped light sources 6 and 6', and at its home position 25, the entire area of the reference optical characteristic section 3 in the main scanning direction (in the direction of the broken line 25 in FIG. 1(B)) and the marker section 4. It is designed to irradiate. Further, the light source device 5 moves in the sub-scanning direction (X direction in FIG. 1(A)) and scans the original on the main scanning area 2. Reference numerals 7, 8, and 9 are reflecting mirrors, which move as the light source device 5 moves so that the optical path from the point where the light source device 5 is irradiated to the lens 10.11 is always equal. Specifically, the reflecting canopy 7 moves together with the light source device 5, and the reflecting mirrors 8 and 9 are allowed to move at a predetermined ratio to the amount of movement of the light source device 5 so as to satisfy the above-mentioned conditions. Reference numerals 10 and 11 designate imaging lenses which, when the original on the reference optical characteristic section 3, marker section 4 and main scanning area 2 are irradiated by the light source device 5, reflect light from the reference optical characteristic section 3, the marker section 4 and the main scanning area 2 through the reflecting mirrors 7-9. An image is formed on the light-receiving surface of the image sensor.

00D1 and 0OD2 are solid-state image sensors that are image pickup devices, and are composed of charge-coupled devices, MOS transistors, or the like, and are electrically scanned in the main scanning direction.

In FIG. 1(B), 14 is a reference mark when placing the original, and 15 is a sensor for detecting the home position 25 of the light source device 5, and its output is controlled via the control mechanism shown in the cine. to adjust the position of the light source device 5.

To explain the operation of the device shown in FIG. 1, when the light source device 5 is at the home position 25 and irradiates the reference optical characteristic section 3, the marker section 4 is also irradiated, and the reflected light is transmitted to the reflecting mirrors 7 to 9 and the imaging section 3. The light passes through lenses 10.11 and is received by solid-state image sensors OODl and 00D2. The signals indicating this shading characteristic also include signals due to reflected light from the marker section 4. This invention replaces the signal from the reflected light from the marker section 4 with a signal from other parts, especially a signal from a part immediately before the marker part 4, and provides a mirror image based on the presence of the marker part 4 for shading correction. This is an attempt to avoid the impact. This will be explained in detail with respect to FIG. Next, the light source device 5 moves to the main scanning area 2, and in the sub-scanning direction (X direction) in FIG. 1(A).
The document is scanned in both the main and sub-scanning directions. The signals that read the original are sent by solid-state image sensors 0ODl and 00D.
2 and processed by the circuits shown in FIGS. 2 and 4, which will be described later. When the IIX scanning is completed, the light source device 5 returns to its home position 25.

Regarding a specific example of the shading correction section in this invention (FIG. 2) FIG. This shows a circuit configuration for replacing with the immediately previous signal, and shows a case where the output of the image sensor 00D1 is processed. Note that since scanning is performed in the Y direction in FIG. 1(E), that is, from the document reference mark 14 toward the center of the document, in this case, the signal from the marker section 4 appears in the latter half of the main scanning cycle.

In FIG. 2, when starting shading correction, the selector 5EIil is switched to the A side and the selector 5EL2 is switched to the 0 side. The bit-serial image signal from the image sensor 00D1 is amplified by the amplifier 31 and converted into a digital signal by the AD converter 32. This digital signal is sent to the random access memory IJ 33 (RA under fl
It's called M. ) is written down. Address control of the RAM 33 is performed via an address counter 33' using a clock signal that is synchronous with the clock signal of the clock generator 34 for the image sensor 0ODl.

The address comparison circuit 3 then compares this address signal with the address code of the address code switch 35, which is set with the address corresponding to the location immediately before the marker section 4.
6, and when a match is obtained, the selector 5ICL3 is switched to the D side, and the digital value at that time is held in the latch circuit 37, and thereafter held in the latch circuit 37 until the main scanning cycle is completed. Continue writing the value to RAM33.

Following the above shading sequence, the light source device 5
At its home position, the reference optical characteristic section 3 is irradiated once more, and then the document is scanned.

In these cases selector s! L1 is switched to the B side,
The image data obtained by reading the marker section 4 and the original are multiplied by hand into one of the read-only memories (hereinafter read-only memory is referred to as ROM). Multiplication P, OM
The other input of 38 is given a signal from AM33 containing the shading value obtained in the shading sequence described above, and the multiplier ROM 3B receives a signal that is in a synchronous relationship with the clock signal of the clock generator 34. The address control is performed via the side address counter 38'.This multiplication ROM 38 is designed to output a code m/n when the input value of the RAM 33 is n and the image data is m. Once again, shading is corrected by this logic.The output from the multiplication ROM 3B is compared with the output of the dither ROM 39, which is a threshold value determination circuit, in a comparison circuit 40, and binarized image data is obtained. , this is input to shift memory 1 (41).

A signal synchronous with the clock signal of the clock generator 34 is input to the main scanning counter 42 for the dither ROM 39 . The sub-scanning counter 43 is the main scanning counter 42
A count pulse is input at every fixed count of , and a synchronous relationship with the sub-scanning of the light source device 5 is maintained. Note that the signal read from the marker section 4 is used in a connection processing section to be described later.

As mentioned above, in the shading sequence in the apparatus shown in FIG. 2, the signal from the marker unit 4 provided for connecting the outputs of multiple image sensors is replaced with the signal from the immediately preceding position, so it can be easily configured. The influence of the marker section 4 on shading correction can be avoided. If reading the shading characteristics and reading the marker section 4 are performed at different positions, when the light source device 5 illuminates the reference optical characteristic section 3, the light reflected by the marker section 4 will be picked up by the image sensors 00D1 and 00D2. Since it is necessary to prevent the light from falling and to separately irradiate the marker section 4, the position control of the light source device bt 5 becomes complicated, but the apparatus shown in FIG. 2 can simplify this. Further, the signal may be replaced with a signal other than the immediately preceding signal, for example, a signal immediately after the marker section 4.

Regarding connection processing of outputs of a plurality of image sensors in this invention (Figs. 3 to 5) Next, a plurality of image sensors, for example, a solid-state image sensor 00D
A means for automatically processing the output signals of 1 and 00D2 will be explained. In the same way as the output of the solid-state image sensor 00D1 is stored in the shift memory 1 in FIG. 2, the output of the solid-state image sensor 0OD2 is stored in the shift memory 2 (FIG. 4). Figure 3 shows the principle of connection processing, where a is the scanning area of 0ODl, and b is the scanning area of 0ODl.
The scanning area D2 is shown, and the scanning direction Y corresponds to the scanning direction Y of FIG. 1(B). When the light source device 5 is at the home position 25 and illuminates the marker section 4, the last 128 bits of the bit serial signal from 00D1 are output to the third
In FIG. 0, the first 128 bits of the bit serial signal from 0OD2 are shown in d. Here, 128 bits are
When the resolution is around 16 bits, this corresponds to 8 strips of width on the original surface.

However, if the ranges scanned by the two optical systems are set to overlap as described above, the 12
A white bit always appears before and after the 8 bits, and the black bit corresponding to the marker section 4 described above is sandwiched between them. Therefore, the number of lower white bits (L, w,
) and the upper white pick in the output of 0OD2) i (tr, w,
) and the number of black bits (B) are thinned out and connected when reading from the shift memory, and 00
The output signals of D1 and 0OD2 are extracted as continuous signals.

Next, FIG. 4 shows the connection processing section that executes the above operation. As shown in FIG. The manner of extraction will be explained. The basics of this processing are to insert data 16 times each in 8-bit units, and to develop this into RAM. This device operates on a write clock signal φ and a read clock signal φ3. First, the central processing unit t (hereinafter referred to as OPU) sets the write address counter 1 and the read address counter 2 to a down count mode. Note that the read address counter 1 is always preset to up count mode.

Then, set address 2592 (A20H in hex code) to I10 register 1, and set address 8 (A20H in hex code) to I10 register 3.
Similarly, set 8H). In this circuit, the CPU is
When the test terminal T of the register 4 is activated, a video enable signal (IN in FIG. 5) indicating one main scanning period is generated once in a reading multi-circuit (not shown), and along with this, the bit serial signal from 0ODI and 0OD2 is generated. It is designed to send out video signals.

The video enable signal IN is input to each set terminal S of 7 lip-flops 1 and 2 in FIG. 4, and the video signal from 00D1 is input to shift memory 1 (shift memory 4 in FIG.
Same as 1. ) and 8-bit shift register 1, OOD
,ii! The video signal from is input to a shift memory 2 and an 8-bit shift register 2. Both 8-bit shift registers 1 and 2 start a shift operation upon activation of the video enable signal, and end the same operation in response to a count completion signal RPO1 from write address counter 1 and read address counter 2, respectively.

Note that this operation is performed via seven lip-flops 1 and 2, respectively.

Therefore, when the OPU activates the test terminal T mentioned above,
When the video enable signal ends, the last 8 bits of the signal from 00p1 remain in 8-bit shift register 1, and the first 8 bits of the signal from 0OD2 remain in 8-bit shift register 2. become. Next, the OPU reads the contents of these shift registers and
Expand on AM. To process the next 8 bits, step 1
Set the address (2592-8) in the 0 register 1 and the address (8+8) in the 10 register 3, and perform the same processing as above. These processes are repeated <1+ 16 times to output 128 bits.

When the calculation of the stitching amount is completed, the document is scanned, but prior to this, the OPU writes 250
Address 4 to I10 register 5 (2592 one connection amount)
Set the street address. This situation is shown in Figure 3 g and h, where g shows an output of 0ODl, which is 8 ODl in the margin from the beginning.
8 pits), 14B, 2376 equivalent to 5m worth of information
bit, 128 bits for bridging processing, total 2592
Bits vary, while the same diagram shows the output of 00D2,
This also amounts to a total of 2592 bits, but the first O
ON indicates the amount of connection. Note that the video output is multiplexed via OR circuits on the output side of the shift memories 1 and 2.

Figure 5 shows the video enable signal (IN), the output signal from 00D1 (OODI), and the output signal from 00D2 (
3 shows the time relationship between OOD2) and write clock (φ2). In addition to the above, the register 4 in the middle part 10 in FIG.
This is for making selections. The OPU in FIG. 4 also controls the shading correction section shown in FIG. 2, and the RAM and ROM in FIG. 4 can also be used as those in FIG. 2.

Although an example in which the present invention is applied to a device with a fixed original and a moving light source has been described above, the present invention can be similarly applied to a device with a fixed light source and a moving document, and transmitted light can be used instead of reflected light. You can also use Further, the number of image sensors is not limited to two, but may be three or more.

Effects of the Invention Based on the above-described configuration and operation, the present invention provides a simple configuration and a complicated movement control of a light source device when performing shading correction in an information reading device equipped with a plurality of image sensors. It is possible to avoid the influence of the presence of the marker section for connecting the output signals of the plurality of image sensors without the need for the marker section.

[Brief explanation of drawings]

2 is an explanatory diagram of the shape-in ring in this invention, FIG. 4 is a block diagram of a specific example of a connection processing unit for outputs of a plurality of image sensors in this invention, and FIG. 5 is a connection diagram of FIG. 4. FIG. 3 is an explanatory diagram of the operation of the processing section. In the figure, 3 is a reference optical characteristic section, 4 is a marker section, 5 is a light source device, 33 is a random access memory, 36 is an address comparison circuit, 37 is a latch circuit, 38 is a multiplication read-only memory, 0ODl and OOD 2 is an image sensor A solid-state image sensor is shown. Patent Applicant Canon Co., Ltd./+77 C1, νt Procedural Amendment 11 (Voluntary) October 19, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of Case 1981 Patent Application No. 128074 2 Reading of the name information of the invention Device 3, Relationship with the person making the amendment Patent applicant name (100) Canon Co., Ltd. 4, Agent Address: 105 (Telephone: 434-2859)
)Address: 1-4-4 Shiba Daimon, Minato-ku, Tokyo Voluntary amendment 6, Number of inventions increased by the amendment 8, Details of the amendment Drawings (Figure 1 (A) and Figure 1 013) will be amended as shown in the attached sheet. 9. List of attached documents (1) One document containing drawings (A) and (2) of Figure 1

Claims (3)

[Claims] (1) A plurality of image sensors arranged side by side in the main scanning direction, a reference optical characteristic section for shading correction provided with a marker section for connecting the outputs of the plurality of image sensors, and read by the image sensor. means for performing shading correction by replacing an output corresponding to the marker section during output by the reference optical characteristic section with an output from a section other than the marker section. (2) The information reading device according to claim (1), wherein the image sensor is a solid-state image sensor. (3) The information reading device according to any one of the above claims, wherein the output other than the marker portion is an output from a location immediately before the marker portion.