JPH0614159A - Image scanner reading method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to an image scanner reading method, and more particularly, when a condition for stopping the reading occurs during the reading operation of the image scanner in relation to the processing progress state of the host processor. The purpose is to reduce the number of intermediate stop conditions and reduce the number of intermediate stop conditions. In an image scanner device for reading a document and outputting image data, a control means for controlling the moving speed is provided, and when the document is read, a halfway stop condition occurs and the moving speed is reduced to restart the reading speed. Is configured to decrease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanner reading method and, more particularly, to an image scanner when a condition for stopping the reading occurs during the reading operation of the image scanner due to the progress of processing of the host processor. Regarding reading method.

[0002]

2. Description of the Related Art In an image processing apparatus or the like, a document is CC
An image scanner device having a photoelectric conversion element such as D reads the image and the host processor processes the image. For example, as shown in FIG. 6, the original 30 is read by the photoelectric reading unit 31 and image data corresponding to the original 30 is output.

The photoelectric reading unit 31 has a light source 32 for irradiating the original 30 and a printed circuit board 33 for receiving the light and outputting image data. Printed circuit board 33
Is a CCD circuit 35 having a CCD and a CCD control circuit for operating the CCD, and an image processing circuit 36 and an image processing circuit 36 for digitally converting (multi-valued) the output of the CCD circuit 35 and binarizing the output. An image data buffer 37 for temporarily holding the image data binarized by
The image data buffer 37 is provided with an interface circuit 38 for holding image data, reading the image data and sending it to the host side.

The original 30 is read by the CCD circuit 35 by moving the original 30 or the photoelectric reading unit 31. The read analog signal is once multi-valued by the image processing circuit 36 and then binarized, and passes through the interface circuit 38 to the image data buffer 3
7 and then output to the host by the interface circuit 38.

Here, the image data buffer 37 is
From the viewpoint of downsizing and price reduction of the image scanner device,
A document whose size is smaller than the size of one page of the document 30 is used.

By the way, in such an image scanner device, during the reading operation of the document 30, the read image data is sent to the host while being temporarily stored in the image data buffer 37. Here, when the reading speed in the scanner device is high, and the image data processing speed in the host is low, such as in a personal computer, when the image data buffer 37 is full and no more data can be stored,
The read operation needs to be paused.

[0007]

In order to temporarily stop the reading operation as described above, it is necessary to stop the movement of the document or the movement of the photoelectric reading unit. Therefore, when the image data receiving speed in the host is slow, such stoppage and restarting accompanying it are frequently repeated, which significantly reduces the total reading speed. Therefore, an object of the present invention is to provide an image scanner device which can reduce the number of restarts and improve the total reading speed without increasing the receiving speed of data on the host side.

[0008]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, an original 10 is read by a CCD circuit 5, and the obtained analog image data is once stored in an image processing circuit 6. After being converted into a value digital signal, it is binarized and sent to the resolution conversion circuit 9.

The resolution conversion circuit 9 converts the resolution of the binarized data transmitted from the image processing circuit 6 when the image data buffer 7 is full and data cannot be stored, and the resolution conversion circuit 9 transmits the resolution at 800 dpi, for example. To convert the data to 400 dpi.

In FIG. 1, 1 is a photoelectric reading unit, 2 is a light source such as a fluorescent lamp, 3 is a printed circuit board,
Reference numeral 8 is an interface circuit.

[0011]

In a normal state, the resolution conversion circuit 9 operates through and outputs the binary image data from the image processing circuit 6 as it is, and the image data is passed through the interface circuit 8 to the image data buffer 7 Stored in.

By the way, when the image data buffer 7 becomes full and data cannot be stored any more and a halfway stopped state occurs, a signal indicating this state is transmitted to a control unit (not shown). As a result, after an intermediate stop,
The control unit reduces the speed of the original document conveyance motor (or photoelectric reading unit conveyance motor) (not shown) to 1 / n, for example, 1/2 of that speed, and at the same time, reduces the resolution conversion rate of the resolution conversion circuit 9 to 1 / n. For example, drop it to 1/2.

In a normal case, the image processing circuit 6 outputs, for example, 4
When the image data of the original 10 is output at a density of 00 dpi, the above-mentioned condition occurs, and if the speed of the original conveying motor is reduced to 1/2, the image processing circuit 6 outputs 800 d.
Image data having a density of pi will be output.
Therefore, if this is converted to 400 dpi by the resolution conversion circuit 9, the reading speed of the original document can be reduced to 1/2 and the processing can be continued as it is, so that the number of occurrences of stop and restart is greatly reduced as in the conventional case. be able to.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. In FIG. 2, the same parts as in FIG. 1 indicate the same parts,
The photoelectric reading unit 1 corresponds to the photoelectric reading unit 31 in FIG. 6, the light source 2 corresponds to the light source 32, the printed circuit board 3 corresponds to the printed circuit board 33, and the CCD circuit 5 corresponds to the CCD circuit 35. The image processing circuit 6 corresponds to the image processing circuit 36, the image data buffer 7 corresponds to the image data buffer 37, and the interface circuit 8 corresponds to the interface circuit 38. And 4
Is a control unit, and 9 is a resolution conversion circuit.

The control unit 4 controls the image scanner device, and controls an original document feeding motor (or a photoelectric reading unit feeding motor), not shown, and a conversion rate in the resolution conversion circuit 9. The moving speed is a relative speed between the document and the photoelectric reading unit 1.

The resolution conversion circuit 9 converts the resolution of the image data transmitted from the image processing circuit 6 in accordance with an instruction from the control unit 4, and is, for example, 1 / n (n is an integer of 2 or more). And has a data buffer 9-1. The capacity of the data buffer 9-1 requires at least two lines.

Prior to a detailed description of one embodiment of the present invention with reference to FIG. 2A, an outline thereof will be described with reference to FIGS. 2B and 2C. In FIG. 2B, when the document 10 is conveyed in the direction of the arrow and is read at a normal speed at a resolution of 400 dpi, if the image data buffer 7 becomes full at L ₀ , the document conveyance motor is temporarily stopped and the document conveyance motor is stopped. Is decelerated to, for example, 1/2. As a result, the area 10-1 and subsequent areas are read at a resolution of 800 dpi.
Therefore, the resolution conversion circuit 9 converts the resolution to 400 dpi.

Even if the conveying speed is reduced in this way, if the image data buffer 7 is further filled up and stopped midway, the speed of the original conveying motor is further reduced to 1 / m as shown in FIG. 2C. (M is an integer of 1 or more) Decelerate and start,
For example, reduce the reading speed to 1/3, 1/4 ...
Accordingly, the resolution in the sub-scanning direction is further reduced to 1/3 and 1 /
Convert to 4 ...

The operation shown in FIG. 2A will be described when the original 10 is moved by the original feeding motor. Manuscript 10
When sending the image data to the host, the light source 2 illuminates the original, the CCD circuit 5 on the printed circuit board 3 receives the original reflection signal, converts it into an analog signal, and the image processing circuit 6 once outputs a multi-valued digital signal. It is converted into a signal and converted into binary image data.
It is sent to the resolution conversion circuit 9 at a resolution of dpi.

At first, since the control unit 4 operates the resolution conversion circuit 9 through, the image data is transmitted to the interface circuit 8 without being controlled by the resolution conversion circuit 9, and the image data buffer is transmitted. It is temporarily held at 7 and sent to the host side.

In this way, the image data is sequentially stored in the image data buffer 7 and sent to the host. However, if the amount of transmission to the host becomes small for some reason, the image data buffer 7 becomes full, You cannot receive.

The interface circuit 8 is in this stopped state.
When the control unit 4 notifies the control unit 4 from the middle, the control unit 4 stops halfway, and the control unit 4 performs control according to FIG. 2C for the document feeding motor (not shown) and the resolution conversion circuit 9 and restarts. For example, control of n = 2 and m = 1 is performed. As a result, the document feeding speed of the document feeding motor is controlled to 1/2. Since the document feeding speed is reduced to 1/2, the image processing circuit 6 outputs the image data having a resolution of 400 dpi up to the image data of 800 dpi in the sub-scanning direction.

At this time, the control unit 4 controls the resolution conversion circuit 9
Is controlled so as to be converted at a resolution conversion rate of 1/2, which is 800 that is transmitted from the image processing circuit 6.
The image data of dpi is converted at 400 dpi, and is stored in the image data buffer 7 via the interface circuit 8 at a storage speed which is ½ of the storage speed up to that time.

Even if the storage speed is reduced in this way, the processing speed on the host side does not improve, and when the image data buffer 7 becomes full again, this state is notified again to the control unit 4. As a result, the control unit 4 decelerates the original feeding motor at a speed of 1 / n + m, that is, the first 1/3, and controls the resolution conversion circuit 9 at a conversion rate of 1/3.

As the conversion processing in the resolution conversion circuit 9, there are the following methods, for example, but the present invention is not limited to these, and other methods may be used.

The area 10-1 in FIG.
The resolution is converted to 400 dpi at the time of reading with i. The areas 10-1 and 10-2 in FIG.
Only the area 10-1 is converted to 400 dpi and output at the time of reading by.

When the areas 10-1 and 10-2 in FIG. 2B are read at 800 dpi, the dot densities of the respective areas are simply added [(area 10-
1) + (area 10-2)] / 2 and output.

It should be noted that when the above method is used, it seems that the missing part of the image data becomes a white line, but the size of the areas 10-1 and 10-2 is the width of the normal sub-area. It is one scanning line width in the scanning direction of 400 dpi, and is actually invisible to the human eye.

A second embodiment of the present invention will be described with reference to FIG. 3, the same symbols as in FIG. 2 indicate the same parts,
Reference numeral 11 is a CCD reading speed adjusting circuit. The CCD reading speed adjusting circuit 11 adjusts the reading speed of the CCD and includes the CCD circuit 5 shown in FIG. For example, in FIG.
As shown in (B), under normal conditions, the CCD 1
The line is read and the document feeding motor is drive-controlled.
Indicates the cycle of the drive control pulse for the document feeding motor.

However, if the image data buffer 7 becomes full and an intermediate stop occurs, the control unit 4 will
As shown in (B), since the drive control pulse for the document transport motor is output at a cycle twice as long as in the normal case, the document transport speed is halved. At the same time, the control unit 4 halves the reading speed of the CCD reading speed adjusting circuit 11, and as shown in (B) of FIG.
One CCD line is read in a time twice as long as in the normal case. In this way, if the intermediate stop condition, that is, the image data buffer 7 becomes full, the motor speed becomes 1/2,
Although the moving time is doubled, the reading speed of CCD is also halved accordingly, and the reading time for one line is doubled. After restarting, the amount sent to the image data buffer 7 is the same time. The transmission amount per unit is reduced to 1/2.

In this way, when the first halfway stop condition occurs, the control section 4 performs the control as shown in the item after the first occurrence in FIG. 3C (for example, n = 2). In this state, if the second halfway stop condition occurs, the control as described in the section after the second occurrence is performed (for example, m = 1). Thus, the amount of output to the image data buffer 7 can be successively reduced without stopping the reading operation on the way.

A third embodiment of the present invention will be described. In the third embodiment, at the beginning of reading a document, the reading operation is performed at a normal reading speed of the image scanner device, for example, 400 dpi. If an image data buffer full stop condition occurs, the control unit determines the amount of data already transferred to the host and the image buffer capacity.
The reading speed after restarting is changed by the following formula.

Read speed = data amount transferred to host / total capacity of image buffer Here, the amount of data transferred to the host of the numerator means the amount of data after restart after the occurrence of the intermediate stop condition,
Indicates the amount of data transferred to the host until the midway stop condition occurs.

By applying this to the first or second embodiment, rational reading speed adjustment can be performed. Next, FIGS. 4 and 5 will be described.
Each of the first to third embodiments is an example of one reading, but when the same original is read a plurality of times, or when a plurality of originals are sequentially read, that is, when reading is performed several times. For example, when executing based on the first embodiment, as shown in FIG. 4, in each reading of the first reading, the second reading ... At the beginning of reading, a predetermined reading speed of the image scanner device is provided. Go back and perform a halfway stop condition. 1 / n for the first time and 1 / (n + m) for the second time.
Thus, the reading speed and the resolution conversion rate can be controlled by the same control each time.

Further, as shown in FIG. 5, in the first reading, the reading speed is set to a predetermined reading speed of the image scanner device at the beginning, and the second and subsequent readings are started from the last reading speed of the previous reading. It can also be controlled.

Of course, such a thing can also be executed based on the second and third embodiments.

[0037]

According to the present invention, when an intermediate stop condition occurs such that the image data buffer becomes full,
Since the amount of data to be transmitted to the image data buffer is reduced by temporarily stopping and changing the control condition and restarting, the number of times the intermediate stop condition occurs can be greatly reduced, and thus the overall reading speed will be significantly reduced. There is no such thing. Moreover, the total reading speed can be improved without increasing the data reception speed on the host side.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the present invention.

FIG. 3 is an explanatory view of a second embodiment of the present invention.

FIG. 4 is an operation explanatory diagram (part 1) when reading is performed a plurality of times.

FIG. 5 is an operation explanatory diagram (part 2) in the case of reading a plurality of times.

FIG. 6 shows a conventional example.

[Explanation of symbols]

 1 photoelectric reading unit 2 light source 3 printed circuit board 5 CCD circuit 6 image processing circuit 7 image data buffer 8 interface circuit 9 resolution conversion circuit 10 original

Claims (4)

[Claims] 1. An image scanner apparatus for reading a document and outputting image data, comprising control means for controlling a relative moving speed of the document and the reading means, wherein a halfway stop condition occurs during a document reading operation and the apparatus is restarted. ,
An image scanner reading method characterized in that the moving speed is reduced to reduce the reading speed. 2. The image scanner according to claim 1, wherein resolution conversion means is provided, and when the moving speed is reduced, the resolution of the signal output from the reading means is converted and reduced. How to read. 3. The image scanner reading method according to claim 1, wherein the CCD reading speed adjusting means is provided to reduce the scanning speed of the CCD when the moving speed is reduced. 4. The image scanner reading method according to claim 1, wherein after the intermediate stop condition occurs, the reading speed at the time of restart is changed according to the amount sent to the host.