JP2643770B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to a precise registration of an image pickup apparatus having a multi-element sensor.

[0002]

2. Description of the Related Art Conventionally, in an image pickup apparatus such as a color image pickup apparatus using a one-dimensional CCD sensor, a registration shift occurs due to a chromatic aberration of an optical system, a position shift of the CCD sensor, and the like.

As a countermeasure against the registration error, in the case of the registration error due to the chromatic aberration of the optical system, in order to suppress the chromatic aberration, an optical system mainly including a reflecting mirror and an optical system using a special material have been developed. We are dealing. The above countermeasures are very expensive, or are not sufficient countermeasures for devices requiring a high angle of view and high resolution.

On the other hand, in the case of a registration error due to a position error of the CCD sensor, the phase of the readout signal from each multi-element sensor is shifted, and pixel alignment is performed by using the closest pixel signal. In this method, the accuracy of pixel alignment is not improved to more than ± 1/2 pixel.

Further, as a countermeasure against the registration error due to the above-described causes, image data obtained from each multi-element sensor is assigned to pixels using image processing technology.
There is also a method of re-pricing all pixel data by resampling to perform pixel matching.

[0006]

In the above-mentioned conventional imaging apparatus, it is necessary to develop an extremely expensive optical system as a countermeasure against registration deviation. However, this method requires a high angle of view and a high resolution. In such a device, sufficient pixel matching data cannot be obtained. Therefore, there is a method of re-sampling all pixel data by resampling to perform pixel matching, but this method has a problem that expensive image processing is required.

It is an object of the present invention to solve the above-mentioned problems and to provide an image pickup apparatus which can reduce image distortion very inexpensively and in real time.

[0008]

Image sensor according to the present invention SUMMARY OF THE INVENTION is an imaging apparatus which <br/> imaging through an optical system of the imaging object relative movement at a constant speed, a plurality of pixel sensors each other
Offset by at least 1 / n pixel (n is a positive integer) in the array direction
And at least m in a direction perpendicular to the arrangement direction.
First and second detector groups each composed of a plurality of multi-element sensor rows shifted by pixels (m is a positive integer), and the first and second detector groups by dispersing incident light from the imaging target. A dichroic film, and a plurality of reading means provided corresponding to each of the plurality of multi-element sensor rows and reading out the image signal of the imaging target detected by the multi-element sensor row independently. First and second image processing means, and read timing of each of the plurality of read means provided in correspondence with each of the first and second image processing means and according to a previously measured shift amount of the optical system And first and second control means for controlling each of the first and second detector groups by the first and second image processing means under the control of the first and second control means. Selectable from multi-element sensor row
Are superimposed on the read image signal.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, an imaging apparatus according to an embodiment of the present invention includes detector groups 1 and 2, image processing circuits 3 and 4, an optical system 5,
And a dichroic film 6.

The imaging device and the imaging target 7 are in a direction perpendicular to the line direction of the detector groups 1 and 2 (direction of arrow A).
Relative motion is performed at a constant speed. Examples of such relative movement include image detection in a facsimile and imaging of the earth side by artificial satellites.

The detector groups 1 and 2 are composed of a plurality of multi-element sensor lines (not shown) and are arranged on the image forming plane of the optical system 5. The image processing circuits 3 and 4 process and output image output signals from the detector groups 1 and 2. Further, the dichroic film 6 is disposed between the detector groups 1 and 2 and the optical system 5 and splits incident light from the optical system 5 and emits the split light to the detector groups 1 and 2 respectively.

FIG. 2 is a diagram showing a multi-element sensor line constituting the detector group 1 of FIG. In the figure, detector group 1
Are arranged in such a manner that each element is shifted by 1 / n pixel (n is a positive integer) in the arrangement direction. That is, the multi-element sensor lines 1a, 1b
Are shifted from each other by 1 / n pixel in the arrangement direction, the multi-element sensor lines 1b and 1c are shifted from each other by 1 / n pixel in the arrangement direction, and the multi-element sensor lines 1c and 1d are shifted from each other by 1 / n pixel in the arrangement direction. I have.

Further, the multi-element sensor lines 1a to 1d are mutually orthogonal to the arrangement direction (hereinafter referred to as orthogonal direction).
Are shifted by m pixels or (m + 1 / n) pixels (m is a positive integer). That is, the multi-element sensor lines 1a and 1b are connected to each other by m pixels or (m + 1) in a direction orthogonal to each other.
/ N) pixels, the multi-element sensor lines 1b, 1c are shifted by m pixels or (m + 1 / n) pixels in the orthogonal direction, and the multi-element sensor lines 1c, 1d are shifted by m pixels or (m + 1 / n) in the orthogonal direction. ) Pixels are shifted.

The detector group 2 is composed of multi-element sensor lines 2a to 2d (not shown), like the above-described detector group 1, and the multi-element sensor lines 2a to 2d are arranged in the arrangement direction with respect to each other. They are arranged with a shift of 1 / n pixel, and are shifted with a shift of m pixels or (m + 1 / n) pixels in the orthogonal direction.

FIG. 3 is a block diagram showing the configuration of the image processing circuit 3 of FIG. In the figure, the detector driving unit 30 of the image processing circuit 3 is connected to each multi-element sensor line 1a of the detector group 1.
To 1d to output a bias voltage and a signal necessary for the operation of the detector to drive the multi-element sensor lines 1a to 1d.

Image output signals from each of the multi-element sensor lines 1a to 1d driven by the detector driving section 30 are amplified by amplifiers 32a to 32d, and the signal voltage is fixed for each pixel by sampling and holding circuits 33a to 33d. And an analog / digital converter (A / D) 34a
Are digitized by .about.34d and output. still,
A clamp circuit may be provided instead of the sampling and holding circuits 33a to 33d, and the signal voltage may be fixed for each pixel by the clamp circuit.

Analog / digital converters 34a-34
The signal digitized by d is stored in the FIFO memory 3
More than several pixels are accumulated in 5a to 35d, and the pixel selector 36
Pixels overlapping the multi-element sensor lines 1a to 1d are simultaneously read by a to 36d. Pixel selectors 36a-3
The pixels read from the multi-element sensor lines 1a to 1d by 6d are stored in the memories 37a to 37d.

The amplifiers 32a to 32d, the sampling and holding circuits 33a to 33d, the analog / digital converters 34a to 34d, and the FIFO memories 35a to 35d.
35d, the pixel selectors 36a to 36d, and the memory 37.
“a” to “37d” are provided corresponding to the multi-element sensor lines 1a to 1d, respectively. Each of the above circuits is controlled by a timing signal from the timing circuit 31.

Although not shown in FIG. 3, the image processing circuit 4 has the same configuration as that of the above-described image processing circuit 3, and the operation of each circuit constituting the image processing circuit 4 is also performed. The same operation as the operation of each circuit of the image processing circuit 3 is performed.

FIG. 4 is a diagram showing the operation of one embodiment of the present invention. FIG. 4A shows a pattern of the imaging target 7 shown in the detector group 1 of FIG. 1, and FIG. 4B shows a pattern of the imaging target 7 shown in the detector group 2 of FIG. I have.

These figures show the operation in the case where the optical system 5 has chromatic aberration. In this case, the pattern interval between the patterns B1 to B5 of the object 7 to be imaged on the detector group 1 is shown. The pattern intervals of the patterns C1 to C5 of the imaging target 7 appearing on the detector group 2 are different from each other.

Therefore, if the image output signals of the detector groups 1 and 2 are read out from the image processing circuits 3 and 4 as they are, even if the images read out from the image processing circuits 3 and 4 are superimposed, the pattern B
1 to B5 do not overlap with the patterns C1 to C5, resulting in color misregistration.

In such a state, for example, when the outputs of all the elements (hatched portions) of the multi-element sensor line 1a are output as image signals, the detector group 2
Are output from the multi-element sensor lines 2a to D2 and D6 parts, output from the multi-element sensor lines 2b to D3 parts, output from the multi-element sensor lines 2c to D4 parts are output from the multi-element sensor lines. 2d to D1, D
The outputs of the five elements are read from the signal processing circuit 4 respectively.

As a result, the outputs of the elements in the D1 to D6 portions of the multi-element sensor lines 2a to 2d read from the signal processing circuit 4 are converted to all the elements of the multi-element sensor line 1a read from the corresponding image processing circuit 3. When an image is superimposed on the output of the above, those outputs almost overlap.

That is, the pattern B1 on the multi-element sensor line 1a overlaps the pattern C1 on the D1 part of the multi-element sensor line 2d, and the pattern B2 on the multi-element sensor line 2a is the pattern C2 on the D2 part of the multi-element sensor line 2a. Overlap. The pattern B3 on the multi-element sensor line 1a overlaps the pattern C3 in the D3 portion of the multi-element sensor line 2b.

Further, the pattern B4 on the multi-element sensor line 1a overlaps the pattern C4 on the D5 part of the multi-element sensor line 2d, and the pattern B5 on the multi-element sensor line 1a is the pattern C5 on the D6 part of the multi-element sensor line 2a.
Overlap.

In this case, since the imaging target 7 is relatively moving at a constant speed in the direction of arrow A with respect to the imaging device, the image captured on the multi-element sensor line 2d of the detector group 2 is m After moving by a pixel or (m + 1 / n) pixels, the image is captured by the multi-element sensor 2c.

Similarly, the image shown on the multi-element sensor line 2c is shown on the multi-element sensor 2b after the imaging object 7 has moved by m pixels or (m + 1 / n) pixels, and the image shown on the multi-element sensor line 2b is The target 7 has m pixels or (m +
1 / n) after moving the pixel, it is reflected on the multi-element sensor 2a.

Therefore, the pattern of the imaging target 7 is shown in FIG.
In the case where the upper and lower patterns are not the same as shown in (1), the timing circuit 31 must control to read the output when the same pattern of the imaging target 7 is captured on each of the multi-element sensor lines 2a to 2d.

In this case, the image shown on the multi-element sensor line 1a of the detector group 1 can be read out at one time, but the image shown on each of the multi-element sensor lines 2a to 2d of the detector group 2 is 4 The data will be read out separately.

That is, first, the image reflected on the multi-element sensor line 2d is
Is stored in a memory (not shown) corresponding to the image data. Next, when the imaging target 7 moves by m pixels or (m + 1 / n) pixels from the position of the multi-element sensor line 2d, an image captured on the multi-element sensor line 2c is displayed. It is stored in a memory (not shown) corresponding to the multi-element sensor line 2c of the image processing circuit 4.

Similarly, when the object 7 is moved by m pixels or (m + 1 / n) pixels from the position of the multi-element sensor line 2c, the image shown on the multi-element sensor line 2b is converted to the multi-element sensor line of the image processing circuit 4. 2b is stored in a memory (not shown) corresponding to 2b. Further, the imaging target 7 is located at m pixels or (m + 1/1) from the position of the multi-element sensor line 2b.
n) An image captured on the multi-element sensor line 2a when the pixel is moved is stored in a memory (not shown) of the image processing circuit 4 corresponding to the multi-element sensor line 2a.

The images respectively stored in the above memories are superimposed on the image shown in the multi-element sensor line 1a when the object 7 is located at the position of the multi-element sensor line 2d.
The image shown in the detector group 1 and the image shown in the detector group 2 almost overlap.

In the above-described method, when the images of the detector groups 1 and 2 are superimposed, a phase shift of 1 / 2n at the maximum remains, but the phase shift can be reduced by increasing n.

The above processing is performed in the multi-element sensor line 1
This is a method for reducing the deviation in the direction parallel to the arrangement direction of the a to 1d and 2a to 2d, but the multi-element sensor lines 1a to 1d,
Taking into account the shift of m pixels or (m + 1 / n) pixels between 2a and 2d, alignment can be performed in the same manner as the above processing.

Further, with respect to image distortion and displacement,
It can be removed in the same manner as the above-described removal of distortion due to chromatic aberration. It should be noted that the amount of shift of the optical system 5 due to chromatic aberration and the amount of shift of image distortion and positional shift are measured in advance, so that the timing circuit 31 can perform control according to the shift amount.

As described above, the multi-element sensor lines 1a to 1d and 2a to 2d of the detector groups 1 and 2 are connected to each other by at least one.
/ N pixels, and a timing circuit 31 for independently reading out image signals of the imaging target 7 detected by the multi-element sensor lines 1a to 1d and 2a to 2d in accordance with a previously calculated shift amount. , The image distortion in real time can be made very small.

Further, unlike the related art, it is not necessary to obtain the distortion and the displacement of the imaging target 7 by performing an image processing on the pixel data by a method such as resampling. It can be carried out.

[0040]

As described above, according to the present invention, in an image pickup apparatus for picking up an image of an object to be moved relatively at a constant speed, the phases of pixels of a plurality of multi-element sensor rows are shifted by at least 1 / n pixel. By reading the image signal of the imaging target detected by each of these multi-element sensor rows independently according to a previously calculated shift amount,
There is an effect that image distortion can be extremely reduced in real time at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a multi-element sensor line constituting the detector group of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of the image processing circuit of FIG. 1;

4A is a diagram showing a pattern of an imaging target shown in a detector group 1 of FIG. 1; FIG. 4B is a diagram showing a pattern of an imaging target shown in a detector group 2 of FIG. 1;

[Explanation of symbols]

 1, 2 detector group 1a-1d, 2a-2d multi-element sensor line 3, 4 image processing circuit 5 optical system 7 imaging target 30 detector drive unit 31 timing circuit 32a-32d amplifier 33a-33d sample hold circuit 34a-34d Analog / Digital converter 35a-35d FIFO memory 36a-36d Pixel selector 37a-37d Memory

Claims (2)

(57) [Claims] 1. An imaging object which moves relatively at a constant speed is optically
An imaging apparatus for imaging through the system, small (n is a positive integer) of at least 1 / n pixel in the array direction of the plurality of pixel sensors in a direction perpendicular to the displacement and the arrangement directions to each other
A first and second detector group consisting of a plurality of multi-element sensor rows shifted by at least m pixels (m is a positive integer), and splitting incident light from the imaging target into the first and second detector groups. A dichroic film for emitting to a detector group, and a plurality of readout means provided corresponding to each of the plurality of multi-element sensor rows and independently reading out the image signals of the imaging target detected by the multi-element sensor row. First and second image processing means comprising: a plurality of reading means provided corresponding to the first and second image processing means, respectively, and each of the plurality of reading means corresponding to a previously measured shift amount of the optical system; And first and second control means for controlling the read timing of the first and second data.
That the image signals selectively read from the multi-element sensor rows of each of the first and second detector groups by the first and second image processing means under the control of the control means. Characteristic imaging device. 2. The image processing apparatus according to claim 1, wherein each of the first and second control units extracts an image signal from a pixel sensor determined according to a shift amount of the optical system among the pixel sensors of each of the plurality of multi-element sensor rows. The imaging device according to claim 1, wherein the imaging device is configured to perform the operation.