JPS5919467A - Information reader - Google Patents

Abstract

PURPOSE:To prevent the error of shading characteristics at the joint processing, by performing the shading correction and attaining the calculating processing of amount of joint with this correcting signal. CONSTITUTION:Plural image pickup elements CCD1, CCD2 arranged in the main scanning direction, a reference optical characteristics section 3 for the shading correction, a marker section 4 for the joint processing of the outut of plural image pickup elements, a storage device (RAM) storing a signal representing the shading characteristics reading the reference optical characteristics section, and a means (multiplication ROM) correcting the signal reading the signal including that of the marker section into a signal stored in the storage device are provided. First, the shading correction is performed and then the calculating processing of amount of joint is attained with the corrected signal and the error due to the shading characteristics at the joint processing is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information reading device, and an object of the present invention is to provide means for preventing errors caused by shading characteristics in connection processing of outputs from a plurality of image sensors.

Regarding conventional technology, in information reading devices used in digital copiers, facsimile machines, etc., a bar-shaped light source illuminates a document on which images or characters are displayed, and the reflected light from the document is received by a solid-state image sensor through an imaging lens, thereby reading the original information. into an electrical signal.

In this type of device, the light distribution characteristics of the light source are not uniform, the reflective mirror is dirty, and as the brightness of the insulator approaches the periphery, the so-called COθ4θ 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 bits of the image sensor. As a means to avoid this, 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 in line in the running direction in order to increase the resolution (2) and increase the 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, an area is provided that is scanned overlappingly by multiple image sensors. It has been proposed to arrange a reference marker and connect the outputs of a plurality of image sensors using signals read from the reference marker.

When the connection process is performed using the signal obtained by reading the reference marker, there is a risk that an error based on the shape ink characteristics described above may occur in the calculation of the connection amount, so it is necessary to prevent this.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is (3) to provide means for preventing errors due to shading characteristics in connection processing in an information reading apparatus equipped with connection processing means for the outputs of a plurality of image sensors.

A further object of the present invention is to first perform shading correction in an information reading device including a shading correction means and a connection processing means for outputs of a plurality of image sensors;
Next, it is an object of the present invention to provide a means that enables calculation of a linkage amount using a signal subjected to shading correction.

Structure of the Invention The present invention includes a plurality of image sensors arranged in parallel in the main scanning direction (in a specific example described later, for example, solid-state image sensors 0OD1 and 0OD2 in FIG. 1); and a reference optical characteristic section for shading correction (also A reference optical characteristic section 3) in FIG. 1; a marker section (also a marker section 4 in FIG. 1) for connecting the outputs of the plurality of image sensors; and a shading characteristic read from the reference optical characteristic section; a storage device (random access memory 53, also shown in FIG. 3) for storing a signal shown in FIG. The present invention is characterized by an information reading device comprising: means for performing correction processing in the multiplication read-only memory 38;

Note that the above reference to specific examples shown in the drawings to be described later does not limit the scope of this invention in any way, and this invention can be modified as appropriate within the scope of the claims.

Furthermore, the information read by the reading device of the present invention includes information contained in documents, photographs, maps, or diagrams on which images, characters, symbols, etc. are displayed, as well as patterns on flat objects such as textile fabrics or textile products. It also includes information such as. 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, in the order of a specific example of its optical configuration, a specific example of a shading correction section, and a process for connecting outputs of a plurality of image sensors.

(5) Regarding the body side (FIGS. 1 and 2) FIG. 1(A) is a side view of a specific example of the optical configuration of the information reading device of this invention. , the same figure (B) shows the top view. In these figures, 1 is a glass plate that is a document placement table, 2
is its main scanning area. Reference numeral 3 denotes a reference optical characteristic section, which is fixedly or movably disposed on the mounting table 1, or placed at a predetermined position thereof. In this specification,
Regarding 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 6 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 is
This corresponds to the first home position 21 of the light source device 5 (the position in the resting state of this device). Reference optical characteristic section 5
Characteristics that affect reflected light, such as color, reflectance, and surface smoothness, serve as standards for shading correction. Reference numeral 4 denotes a marker section, which is arranged on the mounting table 1 in the same sense as the reference optical characteristic section 3, but in the example shown in FIG. The reflected light of the marker section 4 provides a signal for connection processing to be described later, and the marker section 4 is located outside the main scanning area, and the light source device 5 is located at the reference optical characteristic section at the first home position 21. The position is such that the reflected light from the marker section 4 is not picked up by the image sensor when the marker section 3 is irradiated.

Furthermore, the marker section 4 is provided in a portion that is overlapped and scanned 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 has a reference optical characteristic section 6 at its first home position 21.
When irradiated with
21), and the marker section 4 is irradiated at the second home position 22. This irradiation of the marker part 4 needs to be performed not only on the marker part 4 but also on at least the adjacent part in the main scanning direction, but in a normal embodiment, the entire area in the main scanning direction passing through the marker part 4 (7 ).Furthermore, the light source device 5 is moved in the sub-scanning direction (Fig. 1(A)
(in the X direction), and scans the document on the main scanning area 2. Reference numeral 7.8.9 is a reflecting mirror, and as the light source device 5 moves, the lens 10.
11 so that the optical paths up to 11 are always equal. Specifically, the reflecting mirror 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. 10
and 11 are imaging lenses which, when a portion including the reference optical characteristic section 3, marker section 4, and the original on the main scanning area 2 are irradiated by the light source device 5, the reflected light is transmitted to the reflecting mirrors 7 to 11.
9, the image is formed on the light receiving surface of the image sensor. OOD 1
and 00D 2 is a solid-state image sensor which is an imaging device, and is a charge-coupled device or MOE! ), and scanning is performed electrically in the main scanning direction.

Note that 14 in FIG. 1(B) is a reference mark when placing a document, and 15 and 16 are sensors for detecting the first and second home positions 21 and 22 of the light source device 5 (8), respectively. Based on the outputs of these sensors, the position of the light source device 5 is adjusted via a control mechanism (not shown).

To explain the operation of the device shown in FIG. 1, the light source device 5 is located at the home position 21 in its resting state. At the beginning of operation, the light source device 5 irradiates the reference optical characteristic section 3, and the reflected light passes through the reflector 7.8.9, the imaging lenses io and 1i, and is received by the solid-state image sensor 00D1 and ClCD 2, and its output is A signal indicating shading characteristics is obtained. At this time, the characteristics of the light source device 5 and the interval between the home positions 21 and 22 are determined so that the marker section 4 does not lie on the main scanning line. The signals exhibiting the above-mentioned shading characteristics are utilized for shading correction as described below in connection with FIG.

Next, the light source device 5 illuminates a portion including the marker section 4 at the home position 22. The reflected light is received by the image sensors COD I and 00D 2 in the same manner as described above, and the amount of connection between the original reading (9) and output signals is calculated based on the output thereof. The details will be explained in detail with reference to FIGS. 4 to 6.

In this invention, as a sequence procedure, shading correction is first performed, and then joint processing is performed based on the calculation of the joint amount. This is because the calculation of the out-of-accuracy shading value causes misreading of the signal read from the portion including the marker section 4, which causes an error. Next, the light source device 5 moves to the main scanning area 2 7, and the first
The scanner advances in the sub-scanning direction (X direction) in Figure (A) and scans the document in both the main and sub-scanning directions. Signals from reading the original are output from solid-state image sensors ca:o i and 0OD2,
This is processed by the circuits shown in FIGS. 3 and 5, which will be described later. When the document scanning is completed, the light source device 5 returns to its first home position 21.

FIGS. 2A and 2B show a side view and a plan view, respectively, of another specific example of the optical configuration of the information reading device of the present invention. The specific example shown in FIG. 2 differs from the first specific example in that the reference optical characteristic section 3' is provided on the side (10) opposite to the marker section 4 with respect to the main scanning area 2. In the figure, 23 and 24 are the first and second home positions of the light source device 5, respectively, and 15' and 16' are sensors that detect the first and second home positions, respectively. It has the same functionality as the example in the figure. Also, the parts in FIG. 2 indicated by the same reference numerals as in FIG. 1 basically have the same configuration and function as those in FIG. 1.

In the apparatus shown in FIG. 2, in its resting state, the light source device 5
is located at its first home position 26. At the beginning of the operation, the light source device 5 illuminates the reference optical characteristic section 3', and a signal indicating the shading characteristic is transmitted to the solid-state image sensor CCD.
1 and C0D2. Next, the light source device 5 moves in the direction opposite to X in FIG. 2(A), reaches the second home position 24, irradiates the portion including the marker portion 4, and obtains a signal to complete the connection process. After that, the light source device 5
direction, scans the document, and returns to the first home position 23 when this is completed.

(11) In the device shown in FIG. 2, the reference optical characteristic section 5' is provided on the side opposite to the marker section 4, so the position control of the light source device 5 is easier than in the device shown in FIG. Accuracy requirements regarding the characteristics and position control of the light source device 5 and the reflecting mirrors 7 to 9 are relaxed.

Regarding a specific example of the shading correction section in this invention (FIG. 3) FIG. 6 shows a specific example of a shading correction section that corrects a signal read from a portion including the marker section 4 with a shading value, which is a main feature of this invention. Here, only the device for processing the output of the image sensor OOD 1 is shown. In Figure 6, at the start of shading correction,
The selector SEL has been switched to the A side. A bit-serial image signal from the image sensor OOD 1 is amplified by an amplifier 61 and converted into a digital signal by an AD converter 32 (C), and this digital signal is written into a random access memory (hereinafter referred to as RAM) 3B. Address control of this RAM 55 is performed by the image sensor OOD.
The clock signal (12) for j is carried out via the multi-address counter 33' using a clock signal that is in synchronization with the clock signal of the clock generator 34. Next, when scanning the portion including the marker portion 4 and scanning the document, the selector 5FiL is switched to the B side. Then, the portion including the marker section 4 and the image data obtained by reading the document are input to one side of a multiplication read-only memory (hereinafter referred to as ROM) 38 .

The other input of the multiplication ROM 3B is a RAM 5! containing the shading values obtained in the above shading sequence. A signal from , is given.

Address control of the multiplier ROM 3B is performed via an address counter 38' by a clock signal that is synchronous with the clock signal of the clock generator 34. Multiplication R
The OM 58 is built to output a code m/ when the input from the RAM 35 is n and the image data is m, and shading is corrected by this logic. The output of the multiplication ROM 3B is compared with the output of the dither ROM 59, which is a threshold value determination circuit, in the comparison circuit 4o, and (13) binarized image data is obtained, which is stored in the shift memory 1 (41). is input. A signal in synchronization with the clock signal of the clock generator 34 is input to the main scanning counter 42 for the dither ROM 39, and a count pulse is input to the sub-scanning counter 43 at every fixed count of the main scanning counter. Maintains a synchronized relationship with the sub-scanning.

In the apparatus shown in FIG. 3, the signal read from the portion including the marker section 4 is corrected in advance by the signal containing the shading value stored in the multiplication ROM 38, so that the amount of stitching can be calculated without error using this signal. .

Concerning the connection processing of the outputs of the plurality of image sensors in this invention (Figs. 4 to 6)
A means for automatically connecting the output signals of OOD 1 and OOD 2 will be explained. In the same way as the output of the solid-state image sensor caD1 is stored in the shift memory 1 in FIG. 6, the output of the solid-state image sensor OOD 2 is stored in the shift memory 2 (14) (FIG. 5). Figure 4 is from a book showing the principle of connection processing, where a is the scanning area of OOD 1 and b is the scanning area of COD 2.
, and the scanning direction is indicated by Y in the figure. This direction is the scanning direction Y in Fig. 1 (B) and Fig. 2 (B) K.
It corresponds to When the light source device 5 is at the home position 22 or 24 and illuminates the part including the marker section 4, the last 12 bit serial signals from the OOD 1
The 8 bits are shown in Figure 4C, and the first 128 bits of the bit-serial signal from COD 2 are shown in Figure 4D.

Here, 128 bits corresponds to fJ 111 width on the document surface when the resolution is 16 bits/H.

Then, each of these 128 bits is extracted and RA
Expand to M. This state is shown in θ and f in the same figure, but if the ranges scanned by the two optical systems are set to overlap as described above, the 128 bits developed in the RAM will always include white bits before and after. appears, and the black bit corresponding to the marker section 4 described above is sandwiched. So 00D1
The number of bits that is the sum of the number of lower white bits (L, W, ) in the output of C0D2 and (15) of the upper white pits in the output (U, W, ) and the number of black bits (B) is shifted into memory. QC! DI and O
The output of OD 2 is extracted as a continuous signal.

Next, FIG. 5 shows a connection processing section that executes the above operations, and the first aspect of the COD described above will be explained with reference to FIG. The basis of this sampling process is to take in data from both sides 16 times in 8-bit units, and expand this into RAM K. This device operates with a write clock signal φ2 and a read clock signal φ3. First, the central processing unit (hereinafter referred to as CPU) 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 address 2592 (A2 in hex code) is placed in the engineering A register 1.
DH) is set (16), and then address 8 (also 8H) is set in register 6 of 4. In this circuit, when the CPU activates the test terminal T of the register 4, the read circuit (not shown) generates a video enable signal (EN in FIG. 6) indicating one main scanning period once, and along with this, the OOD The button is designed to send bit-serial signals from OOD 1 and OOD 2.

The video enable signal EN is input to each set terminal of 7 lips 70 blocks 1 and 2 in FIG. 5, and the video signal from COD1 is input to the shift memory 1 (shift memory 4 in FIG.
1) and 8-bit shift register 1, 0OD2
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 shifting operations when the video enable signal is activated, and write address counter 1 respectively.
Then, when the count completion signal RPCIK is received from the read address counter 2, the same operation is completed. Note that this operation is performed via seven lip flops 1 and 2, respectively.

(17) Therefore, when the CPU activates the test terminal T mentioned above,
At the end of the video enable signal, 8-bit shift register 1 contains the last 8 of the signals from OOD 1.
bit remains, and COD is stored in 8-bit shift register 2.
The first 8 bits of the signal from 2 will remain.

Next, the CPU reads the contents of these shift registers and expands them onto the RAM. The K that processes the next 8 bits is
Set address (2592-8) in register 1 and register 1, set address (8088) in register 5, and process in the same manner as above. These processes are repeated 16 times to extract 128 bits.

When the calculation of the stitching amount is completed, the document is scanned, but prior to this, the CPU writes 2504 to the register 2 of the process 10.
Set the address to register 3 (2592 one connection amount). This situation is shown in Figures 4g and 4h, where g shows the output of COD i, which is 8 in the margin from the beginning.
8 bits, 2376 equivalent to the amount of information for 148.5n
Total of 128 bits 2592 for bits and connection processing
The same figure shows the output of COD 2, which also consists of a total of 2592 bits, but the first OON
indicates the amount of connection. Note that the video output is taken out via the OR circuit on the output side of the shift memories 1 and 2.

FIG. 6 shows the video enable signal (KN), (ICD
2 shows the time relationship between the output signal from I (ca:ol), the output signal from OOD 2 (COD2) and the write clock (φ2). In addition, the middle work in Figure 5, register 4,
In addition to the above, it is also used to switch the modes of the write address counter 1 and read address counter 2 and to select the address selectors 1 and 2. Figure 85 C
The PU also controls the shading correction section shown in FIG.
The RAM and ROM in FIG. 5 can also be used as those in FIG. 3.

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.
Transmitted light (19) can also be used instead. Furthermore, the number of image sensors is not limited to two, and may be three or more.

Effects of the Invention Based on the above-described configuration and operation, the present invention prevents errors due to shading characteristics in the connection processing in an information reading device equipped with a connection processing means for the outputs of a plurality of image sensors, thereby first performing shading correction. Then, by calculating the amount of linkage using the shading-corrected signal, accurate operation of this type of information reading device can be realized.

[Brief explanation of the drawing]

FIG. 1(A) is a side view showing a specific example of the optical configuration of the information reading device of the present invention, FIG. 1(B) is also a plan view,
FIG. 2(A) is a side view showing another specific example of the optical configuration of the information reading device of the present invention, FIG. 2(B) is a plan view of the same, and FIG. 3 is a specific example of the shading correction section of the present invention. FIG. 4 is a block diagram of an example, and FIG. 4 is an explanatory diagram of the principle of connection processing of the outputs of a plurality of (20) imaging elements in the present invention. FIG. An example block diagram, FIG. 6, is an explanatory diagram of the operation of the connection processing section of FIG. 5. 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, 68 is a multiplication read-only memory, and OOD i and 00D 2 are solid-state image sensors that are imaging probes. Patent Applicant Canon Co., Ltd. Agent Ken Matsuie (21) Life 1 EA/ J---11f CCCII Engineering CCW→p1 CCoZ Engineering α Engineering Publishing] 1 ψ2 Nil 廿几H←L 8 鋪'i″I : (1”') Procedural amendment (voluntary) dated October 1983, Director General of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1980 Patent Application No. 128075 2, Invention title information reading device 3, Relationship with the case of the person making the amendment Patent applicant name (10o) Canon Co., Ltd. 4, Agent 105 (Telephone 434-2859)
) Address: 1-4-4 Shiba Daimon, Minato-ku, Tokyo Voluntary amendment 6, Number of inventions increased due to amendments Drawings Figure 1 (A), Figure 1 03), Figure 2) and Figure 2
Figure (g)) shall be corrected as shown in the attached sheet. 9. List of attached documents (1) 1 document stating the drawing Figure 1 (A) and Figure 1 03) (2) 1 copy of the document stating the drawing Figure 2 (A) and Figure 2 03) General

Claims (2)

[Claims] (1) A plurality of image sensors arranged side by side in the main scanning direction, a reference optical characteristic section for shading correction, a marker section for connecting the outputs of the plurality of image sensors, and the reference optical characteristic section. a storage device that stores a signal indicating the read shading characteristics; and a signal stored in the storage device that stores the read signal including the marker portion)
An information reading device comprising: means for correcting; (2) The information reading device according to claim (1), wherein the image sensor is a solid-state image sensor.