JPH0556228A - Image input device - Google Patents

Abstract

(57) [Abstract] [Purpose] The accuracy of reading an original image is improved by suppressing the deviation of the original reading start position within 1/2 of the reading line width of the line sensor. When a document reading start command is issued, a marker serving as a reference for a document reading starting position which is provided in advance is searched by setting the step feed amount of the line sensor to be half the reading line width of the line sensor or less. When the marker is detected, the line sensor or the document is conveyed by a predetermined distance from the marker detection position and is positioned at the reading start position.
After that, the step feed amount of the line sensor is used as the reading line width of the line sensor to feed by one step to read and input the original image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device for optically reading and inputting an image of an original by using a line sensor, and more particularly to improvement of means for positioning a reading start position.

[0002]

2. Description of the Related Art Conventionally, a line sensor formed by arranging image pickup devices in one direction is fed from the surface of a document while being fed step by step in a reading line width of the line sensor in a direction perpendicular to the arrangement direction of the image pickup devices. There is known an image input device which forms an optical image on the line sensor and reads and inputs the image of the original.

In this type of image input apparatus, generally, a marker serving as a reference of the reading start position is provided at a position deviated from the original reading surface on which the original is placed in the step feed direction of the line sensor. When the reading start is instructed, the line sensor is conveyed to search for the marker, and when the marker is detected, the line sensor is moved by a predetermined distance from the marker detection position to be positioned at the reading start position. ing.

In this case, the step feed amount of the line sensor during the marker search was the same as the step feed amount during the document reading. Therefore, at the time of marker search, as shown in FIGS. 6A, 6B, and 6C, the center of the reading line 61 of the line sensor is p1 → p.
It was moving in the order of 2 → p3 → p4 at a pitch p of one step.

As shown in FIG. 3A, when the marker 62 is not applied to the reading line 1 of the line sensor, the marker 62 has not been detected yet, and therefore one more step is sent. Further, as shown in FIG. 6C, when the marker 62 is applied to the entire width (length in the step movement direction) of the reading line 61, the marker 62 is detected. Is positioned at the reading start position.

However, when the marker 62 is applied to about half the width of the reading line 61 as shown in FIG. 6B, whether or not the marker is detected depends on the environmental change such as temperature. There wasn't. Therefore, in the case of marker detection, the reading start position is sent by a predetermined distance from the position of (b) in the figure, and when the marker is not detected, the reading start position is sent by the same distance from the position of (c) in the figure. Therefore, every time the image reading is started, the reading start position becomes 1
There was a case where the pitch was shifted by the step pitch p.

[0007]

As described above, in the conventional image input apparatus of this type, the reading start position corresponds to the reading line width of the line sensor due to environmental changes such as temperature each time image reading is started. There is a case where the pitch is shifted by one step, and due to this shift, the first line of the original cannot be read.

Therefore, the present invention intends to provide an image input device capable of always reading and inputting a document image with high accuracy by suppressing the deviation of the document reading start position to 1/2 or less of the reading line width of the line sensor. To do.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a line sensor formed by arranging image pickup devices in one direction or a document is read by a line sensor in a direction perpendicular to the arrangement direction of the image pickup devices. In an image input device that forms an optical image from a document surface on a line sensor while feeding and reads and inputs a document image, when a document reading start command is issued, the line sensor or the step feed amount of the document is read by the line sensor. Marker searching means for searching a marker serving as a reference of a document reading start position, which is previously set to 1/2 or less of the line width, and a line sensor or a predetermined distance from the marker detecting position when the marker is detected by the searching means. A reading start positioning control means for conveying the document and positioning it at the reading start position is provided.

[0010]

According to the present invention having such a structure, when a document reading start command is issued, the line sensor or the document is step-fed by 1/2 or less of the line width read by the line sensor to read the document provided in advance. Search for the marker that is the reference for the start position. Then, when the marker is detected, the line sensor or the document is conveyed by a predetermined distance from the marker detection position and is positioned at the reading start position. After that, the line sensor or the document is sent step by step with the reading line width of the line sensor, the light image from the document surface is formed on the line sensor, and the document image is read and input.

Therefore, since the deviation of the original reading start position is less than 1/2 of the reading line width of the line sensor, even if the deviation occurs, the line sensor can reliably read the image of the first line of the original at the original reading start position. be able to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a main part of the apparatus of this embodiment as viewed from the side, and FIG. 2 is a schematic view of the main part as viewed from the top. A rectangular window 12 is formed substantially in the center of the upper surface of the image input device main body 11, and a transparent glass plate 13 is fitted into the window 12. Further, the width direction ruler 14 and the length direction ruler 1 are provided at one end and one side of the glass plate 13, respectively.
5 is attached. And the width direction ruler 14
And the length direction ruler 15 are provided in the vicinity of the contact portion of the original document alignment marker 16 and the original document 17 is placed on the glass plate 13 with its image recording surface facing downward. ing.

A CCD line sensor 18 is formed by arranging CCDs (solid-state image pickup devices) inside the main body 11 in the width direction of the window 12 with a length sufficient to cover the width of the window 12.
A light source 19 made of a fluorescent lamp provided in parallel to the CCD array direction of the CCD line sensor 18, and the light emitted from the light source 19 and reflected by the original 17
Optical lens 20 for forming an image on the D line sensor 18
A line sensor unit 21 that is a unit of and is provided. Then, the line sensor unit 21 is moved in a direction perpendicular to the CCD array direction in the CCD line sensor 18 by the operation of the stepping motor 22.
That is, the structure is such that the window 12 is reciprocally moved in the lengthwise direction within a range that can sufficiently cover the length of the window 12.

On the back surface of the widthwise ruler 14, a reference marker 23 is printed which serves as a reference for the document reading start position A by the CCD line sensor 18. Further, a limit switch 24 for positioning the CCD line sensor 18 is provided inside the main body 11 at an initial position farther back than the position of the reference marker 23.
In FIG. 1, reference numeral 25 denotes a document pressing plate that can be opened and closed.

FIG. 3 is a block diagram showing the control circuit of the apparatus of this embodiment. As shown in the figure, a CPU (Central Processing Unit) 31 constituting the control unit main body is provided with a ROM via an address bus 32, a data bus 33 and a control bus 34.
(Read-only memory) 35, RAM (random
An access memory 36, a DMAC (direct memory access controller) 37, and an external interface 38 are connected.

A motor drive circuit 39 for controlling step drive of the stepping motor 22 and the light source 19 are also provided.
The light source drive circuit 40 for controlling the lighting operation of the CCD line sensor 18, the CCD drive circuit 41 for controlling the reading operation of the CCD line sensor 18, and the limit switch 24 are the I / O ports 42.
It is connected to the CPU 31 via.

The output end of the CCD line sensor 18 is an amplifier 43, an A / D converter 44, and a digital processing circuit 45.
Is connected to the data bus 33 via
The analog signal output by the photoelectric conversion action of the line sensor 18 is amplified by the amplifier 43, and the A / D converter 44
Digitally converted by the digital processing circuit 45 and digital signal processed by the digital processing circuit 45.
U31 can be read.

When the CPU 31 receives an original reading start command from a host device (not shown) via the external interface 38, the program in the ROM 35 is set to execute the control shown in FIG.

That is, when the original reading start command is received in the initial state in which the limit sensor 24 is turned on by the line sensor unit 21, the motor drive circuit 39 is controlled to move the line sensor unit 21 one step forward from the initial position. To move. Next, the 1-line data output from the CCD line sensor 18 is read. Then, it is determined whether or not the reference marker 23 is detected by the CCD line sensor 18. If not detected, the line sensor unit 21 is further moved by one step, one line data is read, and the reference marker 2 is read.
Whether or not 3 is detected is determined. (Marker search means)

The above process is repeated until the reference marker 23 is detected, and if detected, the reference marker 23 is detected.
The line sensor unit 21 is conveyed forward by a predetermined number of steps depending on the printing position and the document reading start position A, and the CCD line sensor 18 is positioned at the document reading start position. (Reading start positioning control means)

Thereafter, each time the line sensor unit 21 is moved forward by two steps by controlling the motor drive circuit 39, one line data output from the CCD line sensor 18 is read and stored in the RAM 36.

The above processing is repeatedly executed for the total number of lines determined by the length of the window 12 and the read line width of the CCD line sensor 18, and when the image input for the total number of lines is completed, the line sensor unit 21 is switched to the limit switch. This control is terminated by returning until 24 is turned on.

Here, the one step feed amount of the line sensor unit 21 by the stepping motor 22 is 1 of the reading line width of the CCD line sensor 18.
It is set to / 2.

Therefore, until the reference marker 23 is detected after the read start command, the steps shown in FIGS.
As shown in (c), the reading line 51 of the CCD line sensor 18 has its center at p1 → p1 ′ → p2 → p2 ′ → p.
It moves in the order of 3 → p3 ′ → p4 at a pitch (½) p of ½ of the read line width.

Then, as shown in FIG. 3A, when the reference marker 23 is not applied to the reading line 51 of the CCD line sensor 18, the reference marker 23 has not been detected yet, so one more step (= (1/2 ) P) sent.
Further, as shown in FIG. 7C, when the reference marker 23 is applied to the entire width of the reading line 51, the reference marker 23 is detected, and the reference marker 23 is sent from that position for a predetermined distance to start reading. Positioned as a position.

However, as shown in FIG. 3B, when the reference marker 23 covers about half of the read line width of the CCD line sensor 18, whether the reference marker 23 is detected or not depends on the temperature or the like. In the case of marker detection, a predetermined distance is sent from the position shown in FIG. 7B to become the reading start position, and when no marker is detected, the same distance is sent from the position shown in FIG. The reading start position is reached.

However, the deviation of the reading start position in this case is one step, that is, half the reading line width of the CCD line sensor 18. Therefore, even if the actual reading start position deviates forward from the designed reading start position A, the document 17 placed on the glass plate 13
Since the image of the line A at the reading start position is formed in a half of the reading line width of the CCD line sensor 18, it can be read by the CCD line sensor 18.

As described above, according to this embodiment, even if the reading start position is deviated due to environmental changes such as temperature every time the image reading is started, the deviation affects the image input accuracy by the CCD line sensor 18. Not to affect
Therefore, the original image can be always read and input with high accuracy, and the quality can be improved.

Further, when the image is read after the reading start positioning, the line sensor unit 21 is moved to CC as in the conventional case.
Since the step feed amount (= 1 step) corresponding to the reading line width of the D line sensor 18 is used for processing, the reading speed does not decrease.

In the above embodiment, the one-step feed amount of the line sensor unit 21 is set to 1/2 of the line width read by the CCD line sensor 18, but the present invention is not limited to this and is set to 1/2 or less. Only then, the effect of the present invention can be sufficiently exerted.

In the above embodiment, the fixed document type image input device is shown. However, even in the movable type image input device, the reference marker 23 is printed on the leading end of the document 17 and the reference marker is used as the line sensor. The present invention can be applied to any type that determines the image reading start position by detecting with. Of course, various modifications can be made without departing from the scope of the present invention.

[0033]

As described in detail above, according to the present invention, the deviation of the original reading start position is suppressed to 1/2 or less of the reading line width of the line sensor so that the original image is always accurately read and input. Therefore, it is possible to provide an image input device capable of improving quality.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a device according to an embodiment of the present invention as viewed from a side surface.

FIG. 2 is a configuration diagram of a main part of the apparatus according to the embodiment as viewed from above.

FIG. 3 is a block diagram showing a control circuit of the apparatus of the embodiment.

FIG. 4 is a flow chart showing control after the CPU receives a read start command in the apparatus of the embodiment.

FIG. 5 is a diagram showing a positional relationship between the reading line of the line sensor and the reference marker when searching for the reference marker in the apparatus of the embodiment.

FIG. 6 is a diagram showing a positional relationship between a read line of a line sensor and a reference marker when searching for a reference marker in a conventional example.

[Explanation of symbols]

11 ... Image input device main body, 18 ... CCD line sensor,
Reference numeral 19 ... Light source, 20 ... Optical lens, 21 ... Line sensor unit, 22 ... Stepping motor, 23 ... Reference marker, 31 ... CPU.

Claims (1)

[Claims] 1. A line sensor formed by arranging image pickup elements in one direction or a document is fed from the surface of the document while being fed step by step in a reading line width of the line sensor in a direction perpendicular to the arrangement direction of the image pickup elements. In an image input device for forming an optical image on the line sensor to read and input the image of the original document, when there is an instruction to start reading the original document, the step feed amount of the line sensor or the original document is read by the line width read by the line sensor. Marker search means which searches for a marker serving as a reference of a document reading start position which is set to 1/2 or less of the line sensor, and when the marker is detected by the search means, the line sensor or a predetermined distance from the marker detection position. An image including a reading start positioning control means for conveying a document and positioning it at a reading start position Power equipment.