JPS63156471A - Linear solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain a secondary differentiation output in real time and to reduce a device by composing each picture element of a group of successively contiguous photodetecting elements, and outputting the difference between the output of the center photodetecting element in the group and the output sum of two other photodetecting element as a device output. CONSTITUTION:Picture elements A1-A2. AN are arranged in series at a photodetection part 11. The respective picture elements adjoin to one another in order and each consist of a group of photodetecting elements (a), (b), and (c) which are insulated electrically from one another. The photodetection area of the element (b) is twice as large as the photodetection area of the elements (a) and (b). A differential amplifier 16 calculates the difference between the output of the element (b) from a transfer part 12 and the output sum of the elements (a) and (c) from a transfer part 13. Consequently, the output of the differential amplifier 16 is the secondary differentiation output of each picture element, so the linear contour of a body which moves in real time can be extracted and neither a conventional arithmetic processor nor a memory is required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a one-dimensional solid-state imaging device (CCD line imaging device) that generates a second-order differential output.

[Prior art]

FIG. 4 is a block diagram of a measurement system using a conventional CCD line imaging device, where 20A is a CCD line imaging device having N pixels (for example, 1024 light receiving elements), 30 is a memory, and 40 is a CCD line imaging device having N pixels (for example, 1024 light receiving elements). 50 is a memory, and 60 is a CRT. FIG. 5 shows the internal configuration of the CCD line imaging device 20A, in which 21 denotes N pixels (light receiving elements) AI, A2, A3...Ak.
. . .A light receiving section in which AN is connected in series, 22 is a transfer section consisting of a transfer COD, 23 is an output section, and 24 is a transfer clock.
It's a pulse.

Next, a case will be described in which this system is used to extract a one-dimensional outline of an object M moving in the direction shown by the arrow in FIG. It receives light through the system and converts it into an electrical signal.

The output signals Vl, V2, V3, . . . VN of each pixel AI, A2, A3, . . . image data). In the arithmetic processing unit 40, the memory 30 is
The above data written in V1, V2, v3...VN
is read out and sequentially executes the second-order differential operation shown below for each pixel, Vk=Vk-(Vk-1+Vk+1)-(1) However, the output signal Vk-1 of the VksK-th pixel Ak: -
The output signal of the 1st pixel Ak+1 is stored as data (one-dimensional image contour data) at a predetermined address in the memory 50. This one
The dimensional image contour data is a differential value of the rate of change of incident light in the pixel arrangement direction (X direction), and the fact that Vk is "present" means contour position information that the pixel Ak is on the contour line of the object M. However, for convenience of explanation, if we focus only on this contour position information, if to is the first sampling time after the object M starts passing under the CCD line imaging device 20A, then from the sampling time to The above-mentioned second-order differential calculation value for the data written to the memory 30 up to the above-mentioned sampling time is transferred from the memory 50 to the CRT 6.
0, the above object M is displayed on the screen of the CRT 60.
The outline of the shaded part is imaged as a discontinuous outline.

[Problem that the invention seeks to solve]

As is clear from the above description, when attempting to extract the contour of a one-dimensional image of an object using the conventional CCD line imaging device 20A, reading from the memory 30, calculation of the above equation (1) (summation), etc. (calculation, subtraction, and division), and writing to the memory 50, each written in the memory 30
Regarding dimensional image data, it is necessary to perform the process 1024 times for the number of pixels, for example, when the number of pixels is 1024, so there is a problem that the data processing time is long.

This invention was made to solve the above-mentioned conventional problems, and it is possible to obtain second-order differential output in real time.
An object of the present invention is to obtain a CCD line imaging device that can be made compact and lightweight.

[Means to solve the problem]

In order to achieve the above object, this invention configures each pixel as a pair of three successively adjacent electrically insulated light receiving elements, and outputs the output of the center light receiving element of each pixel pair and the output of the other two electrically insulated light receiving elements. The configuration is such that the difference from the sum of the outputs of the light receiving elements is used as the device output.

[Effect]

In this invention, since each pixel consists of three sequentially adjacent light receiving elements, the amount of incident light in the pixel arrangement direction is changed by taking the difference between the output of the central light receiving element and the sum of the outputs of the other two light receiving elements. The first-order differential output of the ratio can be obtained using only the hardware configuration.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 11 is N pixels AI, A2, A
3...Ak...AN are connected in series, and each pixel AI, A2, A3...Ak
. . . AN (hereinafter referred to as A as a representative) consists of a pair of light receiving elements a, light receiving element A, and light receiving element C (hereinafter referred to as a pixel pair) which are adjacent to each other and electrically insulated from each other. The light-receiving area of the central light-receiving element is twice that of the light-receiving element a and the light-receiving area of the light-receiving element C. Reference numeral 12 denotes a transfer section consisting of a transfer COD, which transfers the signal output of the central light receiving element in each pixel A. Reference numeral 13 denotes a transfer section consisting of a transfer CCD, which transfers the sum of signal outputs of light receiving element a and light receiving element C in each pixel A.

14 and 15 are output parts, 16 is a differential amplifier, and 17 is a transfer clock pulse. Note that the transfer clock pulses for the light receiving element a and c in the Nth pixel A have the same phase. Note that the arrow indicates the transfer direction.

In this configuration, the signal output Vkb of the light receiving element of the pixel pair constituting the second pixel A is transferred through the transfer section 12 and taken in from the output section 14 to the input terminal of the differential amplifier 15. In addition, the output sum (Vka+Vkc
) is transferred through the transfer section 13 and taken in from the output section 15 to one input terminal of the differential amplifier 16. Differential amplifier 16
Now, the above signal output Vkb and (Vka+
Vk).

vk; vkb-(Vka+vkc) (2
) is output.

Now, at time t, if the reflected image of the object M passing under this CCD line imager 20 is as shown in FIG. Pixel A, ie, AN, on the surface outputs a "presence" output, and the outputs of other pixels A become zero. In other words, only the output of the pixel A whose only part of the light receiving area receives the reflected light from the object M is "present".
(positive value or negative value) is output.

Therefore, the output of the differential amplifier 16 is led to the memory 30 as shown in FIG. 2, and the output to each pixel is written as data (one-dimensional image contour data) to the corresponding address of the memory 30, and the object M is When the data from the first sampling time to to the sampling time t after the CCD line starts passing under the imaging device is read onto the CRT 60, the CR
The outline of the object M will be imaged as a discontinuous outline on the screen of T60.

In this way, the output of the differential amplifier 16 of this embodiment is a second-order differential output for each pixel A, so if the device of this embodiment is used, the one-dimensional contour of the moving object M can be determined in real time. The conventional arithmetic processing unit described above no longer requires memory.

Note that pixel A in the above embodiment is composed of a pixel pair combining three light receiving elements a, b, and C with rectangular light receiving surfaces, but the shape and combination of the light receiving surfaces of light receiving elements a, b, and C are as follows.
Similar effects can be obtained even with a combination of shapes as shown in FIG.

〔Effect of the invention〕

As explained above, in this invention, each pixel sequentially has three adjacent pixels.
Consisting of two photodetectors, the output of the central photodetector and the output of the other two
By taking the difference between the sum of the outputs of two light receiving elements, the first derivative output of the rate of change in the amount of incident light in the pixel arrangement direction can be obtained using only the hardware configuration, and the second derivative output can be obtained without software processing. This makes it possible to perform real-time processing and eliminates the need for an arithmetic processing unit, which has the advantage of making the device smaller and lighter than conventional devices.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a block diagram of a measurement system using the device of the above embodiment, and Fig. 3 is a conventional CCD line imaging device illustrating the operation of the above embodiment. FIG. 6 is a diagram for explaining the operation of the CCD line imaging device. 1m-・Light receiving section, 12.13-Transfer section, 14.15-・
- Output section, 17- Differential amplifier, At, A2, A3 ・
...Ak...AN-pixel, a, b, c-light receiving element. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) In a one-dimensional solid-state imaging device in which a plurality of pixels are arranged in a line, each pixel consists of a pair of three light-receiving elements that are adjacent to each other and electrically insulated from each other, and the center of each pair of pixels is A one-dimensional solid-state imaging device characterized in that the difference between the output of one light-receiving element and the sum of outputs of two other light-receiving elements is used as a device output. (2) The one-dimensional solid-state imaging device according to claim 1, characterized in that the light-receiving area of the central light-receiving element of the pair of pixels is twice the light-receiving area of each of the other two light-receiving elements. .