JPH0698101A - Read area connector for image reader - Google Patents

Abstract

PURPOSE:To prevent joints from being shifted even when originals are shifted in the direction of an optical axis. CONSTITUTION:A link processing part 24 divides the read area of image information for each scanning line into plural area in a main scanning direction, the edge parts of both of read areas are provided with first and second read overlap areas and used for a scanner to read the images of originals. In this case, a DSP 30 finds the pair of connecting picture elements by operating the correlation of image information concerning respective correspondent picture element pairs in both of read overlap areas. On the other hand, an output address control part 32 connects both of read areas with the pair of connecting picture elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reading area connecting device, and more particularly, it uses a plurality of solid-state image pickup devices to divide the reading area of image information for each scanning line in the main scanning direction so as to display the image information of a document. The present invention relates to a reading area connecting device used in a reading image reading device.

[0002]

2. Description of the Related Art For example, an image reading device such as a scanner may read a picture original having gradation such as a photograph or a picture and a line drawing original having no gradation such as characters. In this type of image reading apparatus, image information composed of pixels is divided into a plurality of reading areas in the main scanning direction, and an overlapping reading area is provided at an adjacent end portion of each reading area so that an image of a document is displayed. What to read is known. This image reading device includes a plurality of CCs arranged in the main scanning direction and including a large number of solid-state imaging elements corresponding to pixels.
The D line sensor and a plurality of or single lenses arranged in the main scanning direction corresponding to a plurality of regions and for focusing light from a document on the solid-state image sensor are provided.

As an image reading apparatus of this type, a reference pattern provided on a document table is read, and according to the read boundary position information for each CCD line sensor obtained thereby,
What connects the reading areas is disclosed in Japanese Patent Application Laid-Open No. 31752.

[0004]

SUMMARY OF THE INVENTION In the above conventional configuration,
Since the reference pattern provided on the platen is read and the reading area is connected, when the document is displaced in the thickness direction (optical axis direction), so-called seams such as missing or overlapping image information in the overlapping reading range. Misalignment occurs. An object of the present invention is to make it difficult for a seam shift to occur even if a document shifts in the optical axis direction.

[0005]

A reading area connecting device according to the present invention uses a plurality of solid-state image pickup devices to divide a reading area of image information for each scanning line in the main scanning direction, and to divide both reading areas. The first and second read overlapping areas are provided at the adjacent ends to be used for an image reading apparatus for reading an image of a document. This device comprises a computing means and a region connecting means.

The computing means computes the correlation of the image information relating to each corresponding pixel pair in both read and overlap areas to obtain the connected pixel pair. The area connecting means connects both reading areas with a connected pixel pair.

[0007]

In the reading area connecting device according to the present invention, the calculating means calculates the correlation of the image information regarding each corresponding pixel pair in both reading overlapping areas to obtain the connecting pixel pair. Then, the area connecting means connects both reading areas by the connected pixel pair. Here, the correlation of the image information regarding each pixel pair is calculated, and the reading regions are connected based on the calculation result. Therefore, even if the document is displaced in the optical axis direction, proper connection can be performed, and seam displacement is unlikely to occur.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an image reading apparatus (hereinafter referred to as a scanner) 1 adopting an embodiment of the present invention. The scanner 1 has a lower frame 2 and an upper frame 3 arranged on the lower frame 2. A document placing device 4 is arranged on the upper surface of the lower frame 2.

As shown in FIG. 2, a transmission light source 7 for slit exposure of a transparent original is provided below the original placing device 4.
Are arranged. The document placing device 4 has a document table 5 that is movable in the sub-scanning direction shown by the arrow in FIG. 2, and a drive mechanism 13 that drives the document table 5. Manuscript table 5 is 19 × 2
A document 6 up to a size of 5.4 inches can be placed, and the document is sandwiched by a pair of upper and lower glass plates.

On the upper frame 3, a reflection light source 8 for slit-exposing a reflection original and four CCD line sensors 10a arranged side by side in the main scanning direction (depth direction in FIG. 2).
10 to 10d are arranged. CCD line sensor 10
Each of a to 10d is composed of, for example, 7500 pixel CCD elements arranged in series in the main scanning direction. Therefore, the original 6 of 19 inch size is 300
It is readable with 00 pixels. In addition, at the ends of the adjacent CCD line sensors 10a to 10d, as shown in FIG.
As shown in FIG.
Is provided.

The optical system 9 includes a reflection mirror 11 that bends the light from the original 6 by 90 ° in the horizontal direction, and CC from the light from the original 6.
And a lens 12 for forming an image on the D line sensors 10a to 10d. Four lenses 12 are arranged in parallel corresponding to the CCD line sensors 10a to 10d. The scanner 1 includes a CPU 20 as shown in FIG. The CPU 20 is connected to the line sensor activation unit 22, the preprocessing unit 23, the connection processing unit 24, and the postprocessing unit 25 via the address data bus 21. The line sensor activation unit 22 includes the CCD line sensors 10a to 10a.
Drive 10d. The pre-processing unit 23 performs processing such as shading correction and gradation conversion on the image information obtained from the CCD line sensors 10a to 10d.
The joining processing unit 24 connects the reading area, which will be described later. The post-processing unit 25 performs processing such as unsharp masking, data compression, and data output.

As shown in FIG. 4, the connection processing section 24 includes a digital signal processor (hereinafter referred to as DSP) 30. The DSP 30 has the configuration shown in FIG.
It has an internal memory 39 for storing the image data of the read overlap area DR of 00 pixels and the connection position data in the read overlap area DR. The DSP 30 includes a preprocessing unit 23.
To the main scanning clock MSCL from a clock generator (not shown). The DSP 30 takes in the image data of the read overlap region DR on the basis of the count value of the main scanning clock MSCL, and the internal memory 3
A predetermined correlation calculation process is performed on the image data stored in 9 to calculate a connection address indicating a connection position in the adjacent line sensors 10a to 10d. The calculated connection address is given to the output address control unit 32.

The image data supplied from the preprocessing unit 23 is selectively output to either one of the two line memories 33 and 34 via the changeover switch 36. Each of the line memories 33 and 34 has a capacity for storing image data of all pixels of the four CCD line sensors 10a to 10d. The input addresses of the line memories 33 and 34 are controlled by the input address counter 31.
The input address counter 31 has a main scanning clock MSCL.
The input address counter 31 selectively outputs the input address to the line memories 33 and 34 via the changeover switch 37 according to the counting result.

The output address control unit 32 selectively supplies the connection address supplied from the DSP 30 to the line memories 33 and 34 via the changeover switch 37. In one of the line memories 33 and 34, the address addressed by the input address counter 31
Image data is input from the preprocessing unit 23. At this time, in the other line memory, the output address control unit 3
The image data is output from the output address determined by 2 to the post-processing unit 25 via the changeover switch 38.

The changeover switches 36, 37, 38 are controlled by the changeover unit 35, respectively. The switching unit 35 is supplied with a sub-scanning clock SSCL that is output in synchronization with the main scanning clock MSCL.
Each changeover switch 36, 37, 38
To toggle. That is, each time the reading of the image data of one main scanning line is completed, the changeover switches 36, 37, 38 are switched to change the line memories 33, 3
The input and output at 4 alternate.

Next, the general operation of the scanner 1 will be described. When the manuscript 6 is mounted on the manuscript table 5 and the operator instructs to start scanning, the transmissive light source 7 or the reflective light source 8 is turned on, and the manuscript table 5 moves in the left-right direction (sub-scanning direction) in FIG. Is started. When scanning is started, the light transmitted or reflected on the original 6 is reflected in the horizontal direction by the reflection mirror 11 and enters the lens 12. The light incident on the lens 12 forms an image on the CCD line sensors 10a to 10d and is converted into an electric signal corresponding to the image.

The converted electric signal is first preprocessed by the preprocessing unit 23. Then, in the joining processing unit 24,
A connection address indicating a connection pixel in the read overlap region DR of the line sensors 10a to 10d is calculated by the DSP 30 and given to the output address control unit 32. Here, FIG.
For example, the pixel group 7 of the pixel data group a in the read overlap region DR of the CCD line sensors 10a and 10b.
In the pixel groups 400 to 7499 and the pixel groups 0 to 99 of the pixel data group b, the pixel pair to be the joining position is determined from the corresponding 100 pixel pairs. Here, the correspondence relationship between each pixel pair is the pixel group 7400 of the pixel data group a.
.About.7499 and the pixel groups 0 to 99 of the pixel data group b cannot be changed. For example, when the pixel (m-2) in the data group a is to be connected, the data group b
Then, the pixel (n-2) is the connection target. In correlation calculation,
Correlation calculation is performed for each pixel pair without changing this correspondence.
The process is performed in SP30, and both reading regions are connected by the output address control unit 32 in the pixel pair having high correlation. The correlation means the CCD line sensor 10 in the raster scan.
The degree of coincidence of 12-bit data for each pixel read in a to 10d.

Next, the control operation of the DSP 30 will be described with reference to FIGS.
This will be described based on the flowchart shown in Note that these control operations are performed in real time. First, FIG.
Initial setting is performed in step S1. Here, the maximum number of repetitions R and the connection position mi are set to initial values and stored in the internal memory 39. In step S2, the connection position mi
Is read from the internal memory 39. In step S3, the number of repetitions i is set to "1". The connection position mi indicates the address position of the connection data in the internal memory 39 of the DSP 30 for the data in the read overlap area DR.

At step S4, the main scanning clock MSC
Based on L, the input of image data in the read overlap area DR is awaited. When the image data in the read overlap region DR arrives, the process proceeds to step S5. In step S5, the image data provided from the CCD line sensors 10a to 10d via the preprocessing unit 23 is stored in the internal memory 39. In step S6, a correlation calculation process described later is performed. In step S7, the connection position mi obtained by the correlation calculation process is stored in the internal memory 39. In step S8, the repeat count i is incremented.

In step S9, it is determined whether or not the number of repetitions i exceeds "3". That is, it is determined whether or not the connection positions for the number of connections between the CCD line sensors 10a to 10d have been calculated. The number of connections is one less than the number of line sensors 10a to 10d. Therefore, in this embodiment, there are four CCD line sensors, which is three. From this determination, it is determined whether or not the connection process for one main scanning line is completed. When it is determined in step S9 that the number of repetitions i does not exceed "3", the process returns to step S4 and waits for input of data of the next read overlap region DR. If it is determined in step S9 that the number of repetitions i exceeds "3", the process proceeds to step S10.

In step S10, it is determined whether the scanning in the sub-scanning direction has been completed. If it is determined that the scanning in the sub-scanning direction has not been completed, the process returns to step S2, and the process for the next main scanning line is performed. When it is determined in step S10 that the sub-scanning is completed, the process ends. In the correlation processing of step S6, in step S21 shown in FIG. 6, the correlation value SE at the connection position mi (or the initial value connection position mi) determined in the data group a one main scanning line before is calculated.
Here, the image data a _{m-11 to} a _{m + 11} , b _n-11 in the total of 21 pixels of the target pixel m, n and the 10 pixels before and after it.
The following correlation calculation is performed using ~ bn _{+ 11} .

[0022]

[Equation 1]

Subsequently, the front correlation value SEF and the rear correlation value SEB are calculated with respect to the pixels m-1, m + 1, n-1, n + 1 before and after the pixel of interest m, n. However, the previous correlation value SEF is the pixel of interest m-1 in the data group a.
And the target pixel n-1 in the data group b. The post-correlation value SEB is the data group a.
It is a correlation calculation result regarding the target pixel m + 1 in the above and the target pixel n + 1 in the data group b.

[0024]

[Equation 2]

[0025]

[Equation 3]

In step S24, the correlation value SE, the pre-correlation value SEF, and the post-correlation value SEB are compared to determine whether or not the correlation value SE is the minimum. If it is determined that the correlation value SE is the minimum, it is determined that the correlation at the current connection position mi is high, and the process proceeds to step S25. In step S25,
The connection position mi read in step S2 is substituted for the calculated position M. In step S26, the shift 1 process shown in FIG. 7 is performed.

In the shift 1 process, first, step S31
Then, the calculated position M is substituted for the connection position mi. Step S
In 32, a connection address is calculated from the obtained connection position mi, the calculated connection address is output to the output address control unit 32, and the process returns to the main routine. If it is determined in step S24 in FIG. 6 that the correlation value SE is not the minimum,
Control goes to step S27. In step S27, it is determined whether or not the previous correlation value SEF is the smallest among the three correlation values. When it is determined that the previous correlation value SEF is the minimum, the process proceeds to step S28. In step S28, the shift 2 process shown in FIG. 8 is performed.

Here, first, in step S41, a counter value r for counting the number of processes is set to "0",
The connection position mi is substituted for the calculated position M. Step S42
Then, the counter value r is incremented. Step S
At 43, the calculated position M is decremented. As a result, the target pixel pair moves to the left in FIG. In step S44, the previous correlation value SEF is substituted into the correlation value SE. In step S45, the previous correlation value SEF for the new correlation value SE is calculated. In step S46, it is determined whether the previous correlation value SEF is larger than the correlation value SE. If it is determined in step S46 that the previous correlation value SEF is larger than the correlation value SE, the process proceeds to step S47. In step S47, the shift 1 process described above is executed.

In step S46, the precorrelation value SEF is set.
If it is determined that is smaller than the correlation value SE, step S
Move to 48. In step S48, it is determined whether or not the counter value r has exceeded the number of repetitions R set at the time of initial setting. If it is determined that the number of repetitions R has not been exceeded, the process returns to step S42, and the pixel pair of interest is further moved to the left side in FIG. 10 to perform the correlation calculation.

While the front correlation value SEF is smaller than the correlation value SE, the front correlation value SEF is calculated again by shifting the pixel pair of interest one pixel before (left side in FIG. 10). Then, the magnitude of the obtained pre-correlation value SEF and the correlation value SE is discriminated, and the correlation calculation is repeated until the new correlation value SE becomes smaller or the counter value r exceeds the predetermined number R. Then, the position of the pixel pair at the position where the minimum correlation value is obtained is defined as the connection position m.
The shift 1 process is performed as i.

If it is determined in step S48 that the counter value r has exceeded the predetermined number of repetitions R, the process proceeds to step S49. In step S49, the connection position mi before calculation is calculated.
Is substituted for the calculated position M, the process proceeds to step S47, and the shift 1 process is executed. If it is determined in step S27 in FIG. 6 that the front correlation value SEF is not the minimum, the process proceeds to step S29. Here, since the post correlation value SEB is the minimum value, the shift 3 process shown in FIG. 9 is executed.

The processing in steps S51 to S59 in FIG. 9 is the same as the processing in steps S42 to S49 in FIG. The difference here is that the calculated position M is incremented in step S53 to move the pixel pair of interest backward (to the right in FIG. 10) in FIG. 10, and in step S54 the post-correlation value SEB is set to the new correlation value SE. Point and step S
55 for calculating the post-correlation value SEB, and step S56
This is a point for comparing the post-correlation value SEB and the correlation value SE.
Other processes are the same as those in FIG. 8, and the description thereof will be omitted.

Here, as shown in FIG. 10, the target pixel pair in the data group a and the data group b is moved by one pixel to the right side in FIG. 10 without changing the relationship of the pair. For example, the correlation between the target pixel m in the data group a and the target pixel n in the data group b is calculated, and step S
If the determination in 56 is No, the pixel is moved further to the right by one pixel to calculate the correlation. When the correlation value SE becomes the minimum, the process proceeds to step S57 and shift 1 processing is performed.

According to the above-mentioned calculation, in the read overlap region DR, the pair relationship between the pixels of the adjacent CCD line sensors is fixed, the correlation calculation is performed on the target pixel pair, and the target position is determined according to the magnitude of the correlation calculation result. By shifting, the calculation amount becomes smaller and the processing time becomes shorter than that in the case where the correlation calculation is performed at once for all the pixels. In the above embodiment, the CCD line sensor 10 and the lens 1
The same number as 2 is used, but one lens has a plurality of CCs.
The present invention can be applied even when the D line sensor is covered.

[0035]

In the reading area connecting device according to the present invention, the correlation of the image information regarding each corresponding pixel pair in both reading overlapping areas is calculated to obtain the connecting pixel pair, and the both reading areas are connected by the connecting pixel pair. Since they are connected, the seam shift is unlikely to occur even if the document shifts in the optical axis direction.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a scanner adopting an embodiment of the present invention.

FIG. 2 is a schematic sectional view thereof.

FIG. 3 is a block diagram of a control system.

FIG. 4 is a block diagram of a joining processing unit.

FIG. 5 is a control flowchart of the DSP.

FIG. 6 is a control flowchart of correlation processing.

FIG. 7 is a control flowchart of shift 1 processing.

FIG. 8 is a control flowchart of shift 2 processing.

FIG. 9 is a control flowchart of shift 3 processing.

FIG. 10 is a conceptual diagram showing a joining process.

[Explanation of symbols]

 1 Scanner 6 Originals 10a to 10d CCD Line Sensor 24 Connection Processing Section 30 DSP 32 Output Address Control Section 33, 34 Line Memory DR Read Overlap Area

Claims (1)

[Claims] 1. A plurality of solid-state image pickup devices are used to divide an image information reading area for each scanning line in the main scanning direction, and first and second reading overlapping areas are provided at adjacent ends of both reading areas. A reading area connecting device of an image reading device for reading image information of a document, and calculating means for calculating a correlation between image information relating to respective pixel pairs corresponding to both reading overlapping areas to obtain a connecting pixel pair; A reading area connecting device for an image reading apparatus, comprising: area connecting means for connecting the both reading areas with the connecting pixel pair.