JPS61224661A - Picture reader - Google Patents

Abstract

PURPOSE:To obtain original picture reproduction with fidelity even when the length of a joint has a width of plural picture elements by selecting a proportionally shared density for the joint and outputting the result as a picture signal. CONSTITUTION:Since an output CY2 of a section signal generating circuit is logical '1' in the timing when no joint exists, a selector 12 selects an output of a shift register 7 being a noted picture element data and the result is output ted. The CY2 goes to '0' in the timing where a joint exists and shift registers 5, 6 and 7, 8 hold data while the data before and after the noted picture element is outputted. The output of the shift registers 5, 6 and 7, 8 is inputted respective ly to operation circuits 9, 10, and the output of the operation circuits 9, 10 becomes a data input of the selector 11. The output of the operation circuit 10 is selected at the first half of the joint and the output of the operation circuit 9 is selected at the latter half of the joint.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device having a line sensor formed by connecting a plurality of solid-state imaging devices such as CCDs in a substantially horizontal direction.

[Summary of the Disclosure] The specification and drawings disclose that in an image reading device having an image input sensor formed by connecting a plurality of image sensors at intervals of one pixel or more, one or more effective pixels adjacent to each other before and after the joint Calculate the average density of the image data of the section, and calculate the calculated 2
Disclosed is an image reading device that faithfully reproduces an original image by calculating the density gradient within the joint from two average densities and interpolating the missing image data at the joint between the imaging elements.

"Prior Art" Conventionally, in order to make line sensors longer, there has been an effective means of determining the signal level of the data of the connecting bit corresponding to the gap between the line sensors when short sensors are arranged in series in the horizontal direction. There wasn't. Furthermore, as a preprocessing for image signal processing, there was no particular method for interpolating connecting bits of signals having multivalued gradation levels, and as a result, reproduced images had missing images compared to the original images.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned drawbacks of the prior art.
An image reading device with excellent image reproducibility is provided.

Measures for Solving Problem E] The configuration of a basic embodiment for achieving the above problem is described in the first section.
In the figure, 100 and 101 are delay circuits.

Reference numerals 102 and 103 denote average density calculation units of each of the delay circuits 100 and 101, 104 a proportional distribution calculation unit, lO5 an image signal selection means, and 106 a timing generation means for generating the joint timing.

In the embodiment with the above configuration, the proportional distribution calculation unit 104 selects the proportional distribution density 107 calculated by proportionally distributing the average density calculated by the average density calculation units 102 and 103 to the pixel position within the joint. The 0 selection means 105 outputs the image data 10g of the delay circuit 100 as an image signal in accordance with the timing generated by the timing generating means 106 at times other than the connection 1, and selects the proportional distribution density 107 at the time of the connection. and output it as an image signal.

Example J A more specific example will be described below with reference to one drawing. FIG. 2 shows the structure of a line sensor used in the image reading device of the embodiment. The image reading section 1 includes a solid-state image sensor 1-a such as a COD.

1-b, IC, and the gap between each solid-state image sensor has a width of m pixels. The image signals obtained while scanning such a line sensor 1 in the sub-scanning direction can be obtained continuously in one scan, but of course the image signals of m pixels in the part corresponding to the joint are lost. .

In FIG. 3, if the joint corresponds between the image signals C1 and AO, then m-pixel image data must be restored and inserted between A-1 and AO, which is the image to be restored. The data is restored by the methods shown in the following two examples.

E First Embodiment] Figure 4 is a circuit block diagram representing the first embodiment according to the present invention. The signal IMAGE in Figure 4 is quantized data obtained by A/D converting the output of the CCD line sensor. 0 image data IMAGE is input to the shift register 5 and the signal RC
It is transferred to shift register 6°7.8 in synchronization with L. If the output of the shift register 7 is the pixel of interest Ao in FIG. 3, the outputs of the shift registers 5, 7.8 are A-i,
Corresponds to AX and A2.

By the way, the counter 21 is a line sensor shown in FIG.
1-b,! -c It performs counting with the same period as the number of read pixels for each, and outputs a count-up signal CYi. The count up signal CYI is input to the interval signal generation circuit 22. The 0 interval signal generation circuit 22 is inputted to the 1/2 interval signal generation circuit 23. The count up signal CYI is inputted to the 1/2 interval signal generation circuit 23. Outputs 0''.

Similarly, the 1/2 section signal generating circuit 23 outputs "0" for a period of 1/2Xm. The output CY2 of the 0 section signal generating circuit 22 is input to the AND gate 24. Since lock ICLK is input, RCLK is output when CT4 is °゛l'', but
At the timing of the joint, CT4 becomes °゛0'° only for m pixels, so RCLK is not output.This RC
LK is input as a shift clock to the shift register 5.6°7.8.

It is assumed that the output of the shift register 7 is the pixel of interest. This output is input to the selector 12, and since the section signal generation circuit output CY2 is 1 degree at a timing other than a joint section, the selector 12 selects the output of the shift register 7, which is the pixel data of interest. Output.

At the timing of the joint section, CT4 is “0”.
During this period, RGLK continues to be 0''. The shift registers 5.6 and 7.8 hold the data of the pixel after the pixel of interest and the pixel before it, respectively, as they are output. As shown in Figure 5, when 01 to G- are considered as image data to be interpolated at the seam, B-1°B-2 and B
This corresponds to pixel data of i+82. That is, when correcting the joint, A4 and Ao in FIG.

At * A2 is B-2, 8-1, Hl in Figure 5
, corresponds to B2.

The outputs of the shift registers 5.6 and 7.8 are respectively input to an arithmetic circuit 9.10, and the output of the arithmetic circuit 9.10 becomes a data input to the selector 11.

The select input of the selector 11 is the output of the 1/2 interval signal generation circuit 23. The output of the 1/2 section signal generation circuit 23 is "On" for only half the time, which is the first half of the joint section.
In the second half, it becomes °°l''.

Therefore, in the first half of the joint section, the output of the arithmetic circuit 1O is selectively output, and in the second half of the joint section, the output of the arithmetic circuit 9 is selectively output. This selected output is selector 1
The selector 12 selectively outputs only the section of the joint where the signal CY2 is "o".

The counter 21 uses an unillustrated logic to indicate that CT4 is "o".
When CT4 reaches 1°, the operation is stopped, and when CT4 reaches 1°, the width of one solid-state image sensor is counted again.

By the way, the circuit shown in FIG. 4 when the arithmetic circuit 9.10 in the figure outputs the output of the shift register 6.7 as it is without performing any calculation corresponds to a method in which the nearest adjacent image data is used as is as correction data for the seam. do. In other words, the pixels C1 to Cm/2 in the 0 section are treated as B-1 image data, and the pixels Cm/2+1 to Cl11 in the 0 section are treated as B1 images.If 0m is an odd number, Time m/
You can either cut the remainder off or round up.

Arithmetic circuit 9. A case will be described in which to is an arithmetic circuit that outputs the average value of the output of shift register 5.6 and the average value of shift register 7.8, respectively. In such a case, this corresponds to a circuit that uses the average value of two pixels of the nearest adjacent image data as the correction data for the 0-connection section.

That is, 01~C's/2 = (B-2+B-t)
/ 2Cm/2+INl, a= (82+Bx)
/ 2. Further, when m=2, the data of each adjacent pixel becomes the data of the pixel at the joint.

Second Embodiment" FIG. 6 is a circuit block diagram of a second embodiment according to the present invention. In the figure, counter 21. The operations of the section signal generation circuit 22 and the AND gate 24 are the same as in the first embodiment, and will therefore be omitted.

In FIG. 6, image data IMAGE is input to a shift register 31 and transferred to a shift register 32 in synchronization with 'RCLK. The output of shift register 32 is usually the pixel of interest. During the joint section, the shift registers 31 and 32 continue to stop shifting. At this time, the outputs of the shift registers 32 and 31 that hold the image data before and after the joint are input to the arithmetic circuit 33.

The calculation method in the calculation circuit 33 will be explained. First, the output of the shift register 32 is subtracted from the output of the shift register 31, and the difference is divided by "m+1".

Furthermore, although it is not clear, the quotient is the image transfer lock IC.
It is added to the output of the shift register 32 in synchronization with LK, and the sum is output from the arithmetic circuit 33. In other words, the fifth
As shown in the figure, if 01 to Cm is the section of the joint, and the immediately previous pixel is 8-1, and the immediately following pixel is B1, then 01 to Cm
The n-th interpolated image data Cn between
+ 1) can be obtained by performing the calculation. The selector 12 operates in the same manner as in the first embodiment, and is controlled by the output of the section signal generation circuit 22 in the joint section, and outputs the above-mentioned Cn at the time of the joint bit. The image data after interpolation obtained by such calculation is as shown in FIG.

(Third Embodiment) FIG. 7 is a circuit block diagram of a third embodiment according to the present invention. In FIG. Omitted.

Image data IMAGE is stored in shift registers 41, 42 .
Transferred to 43.44. Since the shift clock of these shift registers is RCLK as explained in the tyth embodiment, the transfer is stopped when transferring image data at the joint, and at that time, the images corresponding to 8-1 and B-2 in FIG. Data is output from shift registers 43 and 44. Further, image data corresponding to Bl, 82 in FIG. 5 is output from the shift register 42.41. These outputs are input to an arithmetic circuit 45. The calculation result by the calculation circuit 45 is input to the selector 12, and according to the value of CY2, which is the output of the section signal generation circuit 22, the calculation result is output from the selector 12 in the joint section, and when the section is other than the joint section, the calculation result is outputted from the selector 12. A pixel, that is, the output of the shift register 43 is selectively output.

The calculation circuit 45 can perform the following two calculations.

(Calculation example 1) Cr= ((21+0.5)(Bl+82)/2'+
(+-n+1.5)(B-1+8-2)/2)/
(+a+2) (fyt calculation example 2) Cn= (B-++ n・(B+ -8-+)l/
(+a+2)=((n-B ÷(m-n+1)l/
(mal) However, n=m+1.

In the case of calculation example 2, the circuit configuration of FIG. 7 is equivalent to that of the second embodiment.

In calculation example 1, CB+ +82)/2 and C
B-1+B-2)/2 is used, and the interpolation data is data that is proportionally distributed using the inverse ratio of the distance between the pixel at the joint and the center position of two effective pixels on the left and right. Calculation example 2
The method is the same, that is, the left and right sides of the joint section are gently corrected.

Further, to show a modification example, in FIG. 7, (q −2) more registers are inserted before the shift register 41, and a shift register (
Let us consider the case where q′ −2) pieces are inserted. In this way, the calculation of the calculation circuit 45 is as follows. The interpolated data of the n-th pixel in the connection 0 is Cn=[(B++B2+...+Bo-+)・(n"(p-1
)/21/q + (B-1+8-24-+B-t
D-1> ) ・(m-n+1,000(q-1)/21/p
]/ (+s+1+(p-1)/2+(q-1)/2)
becomes.

In the above calculation formula, (n+ (p-1)/2) represents the distance from the nth in the joint section to the center position of the leftmost p effective pixels, and similarly, (m-n+1+ (q-1)/ 2
) is the distance to the rightmost q center positions, and the denominator is (m +
1 + (p-1) / 2 + (q-1)/2
1 is the distance to p pixels and q pixels before and after the joint, taking into account the length of the first joint section.

Also, (B+ + 82 +...+ Bo-+)/q
, (B, + + B-2" = + 8-(pl))/P
is the average value of q pieces of data and p pieces of data before and after the first transition section.

That is, in this embodiment, the respective average values are calculated based on the image data of a plurality of pixels before and after the joint, and the interpolated image data Cn of the joint is divided into data that is proportionally distributed in the inverse ratio of the distance to the center position of the plurality of pixels. By doing this, the image data for one section of connection is determined as shown in FIG.

According to the three embodiments described above, even if the line sensor is composed of several chips of solid-state image sensors and the gap between the joints is wide, by applying correction, it is possible to easily make full use of the long sensor with the joints. Also, by setting the number of reference pixels for correction to a plurality of pixels, it becomes less susceptible to noise and the like.

In addition, by interpolating one section of a joint in a multilevel gradation level image signal, interpolation of the joint is performed using image data before the binarized image, so pre-processing such as image processing is possible. It is effective for etc.

[Effects of the Invention] As explained above, according to the present invention, by smoothly restoring the loss of image data that occurs at the joints of solid-state image sensors, faithful reproduction can be achieved even if the length of the joint is multiple pixels wide. Original picture reproduction can be obtained.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of an embodiment according to the present invention, and FIG. 2 is a structural diagram of a line sensor. Fig. 3 is a diagram showing the read image signal, Fig. 4 is a block diagram of the first embodiment, Fig. 5 is a diagram showing one section of line sensor connection, and Fig. 6 is a block diagram of the second embodiment. 7 are block configuration diagrams of the third embodiment, and FIGS. 8 and 9 are restoration diagrams of interpolated image data of the connecting section. In the figure, l: line sensor, 2: chip gap ,5
．． 6,7,8,31.32,41,42゜43.44・
...Shift register, 21...Counter, 11.12
...Selector, 22...Section signal generation circuit, 23.
. . . l/2 section signal generation circuit, 24 . . . AND gate, 9.10, 33.45 . . . arithmetic circuit, 37 .

Claims (1)

[Claims] In an image reading device that has a line sensor formed by connecting a plurality of image sensors in a substantially horizontal direction with a predetermined gap, and outputs an image signal from image data of an original image obtained by scanning the line sensor, the gap is Calculate the average density of the image data in the effective pixel section adjacent before and after , calculate the density gradient in the gap from the two calculated average densities, and calculate the density proportional to the pixel position in the gap from the density gradient. An image reading device that interpolates lost image data in a gap between image sensors by restoring it as an image code in the gap.