JPH08125808A - Image sensor and image read method using it - Google Patents

Abstract

PURPOSE: To provide a sharp image with high sensitivity by adopting the configuration such that the image of the same position of an object is sensed at different field angles by plural sensors respectively. CONSTITUTION: The image sensor 1 consists of three linear image sensors 3A, 3B and 3C. The linear image sensors 3A, 3B and 3C sense an image at a same linear position of a liquid crystal display device 8 via a lens 4 and provide image sensing signals corresponding to the luminous intensity of the sensed image to an adder 5. The adder 5 sums the image sensing signals from the linear image sensors 3A, 3B and 3C. In this case, image data being common elements of the image sensing signals by the linear image sensors 3A, 3B and 3C are amplified by the number of the linear image sensors 3A, 3B and 3C, that is, three times and noise signals not being the common elements are not amplified. As a result, a sharp image is provided with high sensitivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor used in the field of FA (Factory Automation) such as image inspection of liquid crystal display devices and an image reading method using the same.

[0002]

2. Description of the Related Art Generally, an image sensor is a one-dimensional image sensor (line sensor) used in an electronic copying machine or a facsimile, and a two-dimensional image sensor (area sensor) used in a small video camera or the like. Classified as and. Among them, the one-dimensional image sensor is, for example, C
It has a structure in which a plurality of pixels composed of a CD-type solid-state image sensor are linearly arranged, and is capable of capturing a one-dimensional image, and in a direction orthogonal to the pixel arrangement direction. A two-dimensional image can be captured by moving the subject at a constant speed. On the other hand, the two-dimensional image sensor is, for example, C
It has a structure in which a plurality of pixels composed of a CD-type solid-state image pickup device are arranged in a matrix, and a two-dimensional image can be captured even when the subject is stationary.

[0003]

By the way, the conventional one-dimensional image sensor as described above has lower sensitivity than the two-dimensional image sensor, and when performing multi-valued image processing such as gradation display, It took a few tens of seconds to capture an image comparable to that of a two-dimensional image sensor. For this reason, the one-dimensional image sensor cannot be used in image inspection of a liquid crystal display device, which requires, for example, a low-luminance image to be captured at high speed and multivalued image processing such as gradation display. It was Therefore, a high-sensitivity image sensor has been proposed which can shorten the image pickup time by amplifying the image detection signal of the one-dimensional image sensor with an amplifier or the like. However, in such a high-sensitivity image sensor, since the image detection signal of the one-dimensional image sensor captured in a short time is amplified by an amplifier or the like, noise is also amplified and a clear image cannot be obtained. There was a problem. Specifically, for example, in the case of a one-dimensional image sensor using a CCD type solid-state image sensor, the image detection signal of a predetermined one pixel of the one-dimensional image sensor has a waveform as shown in FIG. When this image detection signal is amplified by an amplifier or the like, it has a waveform as shown in FIG. 5B, and noise is also amplified. An object of the present invention is to provide an image sensor capable of obtaining a clear image with high sensitivity and an image reading method using the same.

[0004]

According to the first aspect of the present invention,
In detecting an image of a subject, a plurality of sensors are provided, and each of these sensors detects an image of the same part of the subject from different viewing angles. According to a third aspect of the present invention, in detecting an image of a subject, an image of the same portion of the subject is detected by a plurality of sensors from different viewing angles, and image detection signals from these sensors are added by an adder. .

[0005]

According to the first aspect of the present invention, a plurality of sensors are provided for detecting an image of an object, and each of these sensors detects an image of the same portion of the object from different viewing angles. It is possible to detect the image of the same location of the subject from different viewing angles. According to the third aspect of the invention, in the image detection of the subject, a plurality of sensors detect images at the same location of the subject from different viewing angles, and the image detection signals from these sensors are added by an adder. Therefore, it is possible to amplify the image data, which is a common element of the image detection signals of the respective sensors, by the number of sensors, that is, multiple times, while not amplifying noise that is not a common element. Therefore, the image data can be amplified, and the ratio of noise in the image data can be reduced. As a result, a highly sensitive and clear image can be obtained.

[0006]

FIG. 1 shows an image sensor according to an embodiment of the present invention. This image sensor 1
The case 2 includes three one-dimensional image sensors (sensors) 3A, 3B, and 3C arranged in parallel. Each one-dimensional image sensor 3A, 3B, 3C has a CC on the bottom surface.
A plurality of pixels (not shown) including an image pickup device such as a D-type solid-state image pickup device and a MOS-type solid-state image pickup device are linearly arranged. One-dimensional image sensor 3 in case 2
A convex lens 4 is provided below A, 3B and 3C. The optical axis of the lens 4 is the one-dimensional image sensor 3A,
It is orthogonal to the arrangement direction of the pixels 3B and 3C and the arrangement direction of the respective one-dimensional image sensors 3A, 3B and 3C. 1 each
An adder 5 is electrically connected to the three-dimensional image sensors 3A, 3B and 3C. An amplifier 6 is electrically connected to the adder 5. The image sensor 1 configured as described above is disposed above the table 7 that is movable in the horizontal direction so as to face the table 7. In this case, the three one-dimensional image sensors 3 </ b> A, 3 </ b> B, and 3 </ b> C face the liquid crystal display device (subject) 8 placed at a predetermined location on the table 7, and the liquid crystal display device 8 is mounted via the lens 4. It is possible to receive light from the same linear part. Then, the liquid crystal display device 8 is moved at a constant speed in the direction orthogonal to the pixel arrangement direction (direction of arrow A) along with the movement of the table 7, and the liquid crystal display device 8 is moved.
Image reading.

Next, an image reading method of the liquid crystal display device 8 using the image sensor 1 will be described. First, each one-dimensional image sensor 3A, 3B, 3C detects an image from the same linear portion of the liquid crystal display device 8 via the lens 4. Next, each one-dimensional image sensor 3A,
Image detection signals corresponding to the light intensities of the images detected by photoelectric conversion by 3B and 3C are output to the adder 5, respectively.
Next, the adder 5 adds the image detection signals of the one-dimensional image sensors 3A, 3B, and 3C. Next, the image detection signal added by the adder 5 is amplified by the amplifier 6 and then converted into output specifications. Then, when the above steps are repeated from one end to the other end of the liquid crystal display device 8, the image reading of the liquid crystal display device 8 is completed.

Next, a specific example will be described. FIG. 2 shows a waveform of an image detection signal of a predetermined one pixel of each one-dimensional image sensor 3A, 3B, 3C when a CCD type solid-state image pickup device is used as an image pickup device. In this case, FIG. 2A shows the left one-dimensional image sensor 3A.
2B shows a waveform of an image detection signal of a predetermined one pixel, and FIG. 2B shows a central one-dimensional image sensor 3B corresponding to a predetermined one pixel of the left one-dimensional image sensor 3A.
2C shows the waveform of the image detection signal of the predetermined one pixel, and FIG. 2C shows the right one-dimensional image sensor 3C corresponding to the predetermined one pixel of the left one-dimensional image sensor 3A.
3 shows a waveform of a predetermined one-pixel image detection signal. Next, when the adder 5 adds the image detection signals of the respective one-dimensional image sensors 3A, 3B, and 3C shown in FIGS. 2A to 2C, as shown in FIG.
The image data, which is a common element of the image detection signals of A, 3B, and 3C, is amplified by the number of the one-dimensional image sensors 3A, 3B, and 3C, that is, three times, and noise that is not a common element becomes a waveform of the image detection signal that is not amplified. . Next, when the image detection signal added by the adder 5 is amplified by the amplifier 6 and then converted into the output specification, as shown in FIG. 4, image data having a reduced noise ratio can be obtained.

As described above, in the image detection of the liquid crystal display device 8, the three one-dimensional image sensors 3A, 3B and 3C are used.
And each of these one-dimensional image sensors 3A, 3B,
Since 3C detects images at the same location on the liquid crystal display device 8 from different viewing angles, the three 1D image sensors 3A, 3B, and 3C can detect images at the same location on the liquid crystal display device 8 from different viewing angles. it can.
Further, in the image detection of the liquid crystal display device 8, three one-dimensional image sensors 3A, 3B, 3C detect images at the same location of the liquid crystal display device 8 from different viewing angles, and the respective one-dimensional image sensors 3A, 3B are detected. 3C
Since the image detection signals from 1 are added by the adder 5, the image data, which is a common element of the image detection signals of the respective one-dimensional image sensors 3A, 3B, and 3C, is added to the one-dimensional image sensor 3A,
It is possible to amplify the number of 3B and 3C, that is, three times, while not amplifying noise that is not a common element. Therefore, the image data can be amplified and the ratio of noise in the image data can be reduced. Therefore, a clear image with high sensitivity can be obtained. As a result, it is possible to use in the field of FA such as image inspection of the liquid crystal display device 8 which takes in a low-luminance image at high speed and performs multi-valued image processing such as gradation display.

In the above embodiment, the number of the one-dimensional image sensors 3A, 3B and 3C is three, but the number is not limited to this and may be any plural number. Further, if the number of the one-dimensional image sensors 3A, 3B, 3C is increased, a clearer image with higher sensitivity can be obtained. Further, in the above embodiment,
Although the one-dimensional image sensors 3A, 3B, and 3C are provided separately, the present invention is not limited to this, and they may be provided integrally on the same substrate. Further, in the above embodiment, each one-dimensional image sensor 3
A, 3B, and 3C simultaneously detect images from the same linear portion of the liquid crystal display device 8 through one lens 4, but the present invention is not limited to this, and each one-dimensional image sensor 3A, 3B, and 3C.
You may detect separately via the lens provided for every C. Further, without using the lens 4, the images from the same linear portion of the liquid crystal display device 8 can be obtained by the respective one-dimensional image sensors 3A, 3B, 3 and 3.
C may directly detect. For example, first, the liquid crystal display device 8
A predetermined linear portion of the left side is positioned below the left one-dimensional image sensor 3A, an image of the predetermined linear portion is detected by the left one-dimensional image sensor 3A, and then the liquid crystal display device 8
A predetermined linear portion of the image is moved below the central one-dimensional image sensor 3B, and the central one-dimensional image sensor 3B detects the image of the predetermined linear portion.
The predetermined linear portion may be moved below the right one-dimensional image sensor 3C, and the image of the predetermined linear portion may be detected by the right one-dimensional image sensor 3C. Further, in the above-mentioned embodiment, the sensors are the one-dimensional image sensors 3A, 3A and 3B.
However, the present invention is not limited to this and may be a two-dimensional image sensor. In this case, a clear image with higher sensitivity can be obtained.

[0011]

As described above, according to the first aspect of the invention, a plurality of sensors are provided for detecting an image of a subject, and each of these sensors detects an image of the same portion of the subject from different viewing angles. Therefore, it is possible to detect the image of the same location of the subject from different viewing angles by the plurality of sensors. According to the third aspect of the invention, in the image detection of the subject, a plurality of sensors detect images at the same location of the subject from different viewing angles, and the image detection signals from these sensors are added by an adder. Therefore, it is possible to amplify the image data, which is a common element of the image detection signals of the respective sensors, by the number of sensors, that is, multiple times, while not amplifying noise that is not a common element. Therefore, the image data can be amplified, and the ratio of noise in the image data can be reduced. As a result, a highly sensitive and clear image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image sensor according to an embodiment of the present invention.

FIG. 2 is a graph showing a waveform of an image detection signal of each one-dimensional image sensor of the image sensor.

FIG. 3 is a graph showing a waveform after adding the image detection signals of the respective one-dimensional image sensors.

FIG. 4 is a graph showing a waveform after the added image detection signal is converted into output specifications.

5A is a graph showing a waveform of an image detection signal of the one-dimensional image sensor, and FIG. 5B is a graph showing a waveform after amplification of the image detection signal of the one-dimensional image sensor.

[Explanation of symbols]

 1 image sensor 3A, 3B, 3C 1-dimensional image sensor (sensor) 4 lens 5 adder 6 amplifier 8 liquid crystal display device (subject)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04N 1/19 7/18 B

Claims (4)

[Claims] 1. An image sensor, wherein a plurality of sensors are provided for detecting an image of a subject, and each of these sensors detects an image of the same portion of the subject from different viewing angles. 2. The image sensor according to claim 1, wherein the plurality of sensors detect the image of the subject through at least one lens. 3. An image characterized in that, in image detection of a subject, images of the same portion of the subject are detected from different viewing angles by a plurality of sensors, and image detection signals from the respective sensors are added by an adder. Image reading method using a sensor. 4. The image reading method using an image sensor according to claim 3, wherein the plurality of sensors detect the image of the subject through at least one lens.