JPS63133128A - Optical difference sensor - Google Patents

Abstract

PURPOSE:To obtain a difference signal between two picture information in real time with a high precision by providing two photodetectors and joining respective electric output terminals so that photoelectric characteristics of photodetectors are different in polarity. CONSTITUTION:For example, two PN junction diodes 1 and 2 are so connected that they are different in polarity. If optical waves 5 and 6 having light intensities PA and PB are made incident on diodes 1 and 2 respectively, photocurrents iA and iB corresponding to intensities of incident light flow to diodes 1 and 2, and an addition value iA+iB of two currents is obtained in a connection part 3. If an external circuit which sets the potential of the connection part to, for example, V=0 is set, the sum iA+iB of two currents obtained from the connection part 3 is proportional to a difference PB-PA between light intensities of optical waves incident on two diodes 1 and 2. Thus, the difference signal of light intensity between two optical waves is effectively detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical differential sensor, and more particularly, after detecting a difference between signals related to two incident lights, for example, a difference in light intensity of the incident lights, within a sensor, the difference is detected. The present invention relates to an optical differential sensor suitable for image processing devices and the like having a function of outputting signals.

(Prior Art) As the amount of image information in image processing devices has increased, it has become increasingly common for image processing devices to first convert image information into electrical signals, then perform signal processing, and then perform various types of image processing. There is. It is often done to detect the difference in image information between two of these images, and thereby to determine the relative positional relationship, correlation, etc. between the two images.

Conventionally, when determining the difference in image information between two two-dimensional images A and B, the human-powered image A is first taken from an imaging device such as a CCD, A/D converted, and then stored in a frame memory A such as a RAM.
I can raise it to 1. Next, another human image B is stored in the frame memory B1 in the same manner. And both frames A1, B
Sequential differences are calculated electrically from the data of 1, and from this, 2
The difference between two images A and B was obtained.

However, as the number of pixels in human images increases, this method requires a huge amount of memory capacity, and has drawbacks such as requiring a large amount of time for signal processing. Two other imaging devices A2. The two images A and B are simultaneously manually read using the image pickup device A2.B2. B
A method has been used in which the signals from 2 are read out synchronously and a difference signal between the human images A and B is obtained using an external electric circuit or the like.

However, this method requires two imaging devices, and the positional relationship of the human-powered images on the two imaging devices must be matched with high accuracy, and there are drawbacks such as difficulty in adjusting the optical device for reading the human-powered images. there were.

(Problems to be Solved by the Invention) The present invention is suitable for an image processing device that can obtain a differential signal of image information between two images with high resolution in real time and can perform image processing with a simple configuration. The purpose is to provide an optical differential sensor.

(Means for solving the problem) The optical differential sensor according to the present invention has two photodetecting elements,
The electrical output terminals of the photodetecting elements are connected so that the polarities of the charging characteristics of the photodetecting elements are different from each other.

In particular, in the present invention, analyzers with different deflection axis directions are arranged in front of the input of the two photodetecting elements, or two optical filters with different wavelength selectivity are arranged.
A difference signal of image information regarding two input images is efficiently obtained.

(Example) FIGS. 1, 2, and 3 are explanatory diagrams of an example for explaining the operating principle of the optical differential sensor of the present invention. Of these, FIG. 1 shows a state in which two PN junction type diodes 1 and 2 are connected so that their polarities are different from each other. For example, if light waves 5.6 with light intensities pA and pB are incident on the two diodes 1.2, photocurrents iA and i8 corresponding to the respective incident light intensities flow through the diodes 1.2, and the connection portion 3
The sum of the two currents iA+i, is obtained from . Now, if a voltage ±VR is applied to each of the two diodes 1 and 2 so that they are reverse biased, and the potential of the connection part 3 is set to V, the relationship between the current i flowing through each diode 1 and 2 and the voltage V is If the incident light intensities pA and pB are used as parameters, the result will be as shown in FIG.

That is, as the light intensity P8 of the light wave incident on the diode 2 increases, the current iB increases in the positive direction, and as the light intensity PA of the light wave incident on the diode 1 increases, the current jA decreases in the negative direction.

When an external circuit is set to set the potential of the metal wire part to, for example, V=O, the sum of the two currents obtained from the connection part 3, iA+j3, is the light intensity of the light waves incident on the two diodes 1.2 as shown in FIG. The value is proportional to the difference PB-PA.

As described above, in this embodiment, a difference signal between the light intensities of two light waves is effectively detected by configuring an optical differential sensor by coupling the output ends of two diodes with different polarities.

Figure 4 (A) shows each element of the optical differential sensor shown in Figure 1.
FIG. 2 is an explanatory diagram of an example when formed on the surface of a mold silicon substrate 10, and FIG. 3B is a plan view of FIG.

In FIGS. 4A and 4B, 12° and 13 correspond to the two diodes mentioned above, respectively. Reference numeral 11 is an n-layer with a low impurity concentration, and reference numeral 14 is an n+ layer having a function as a channel stop for separating adjacent elements.

Depending on the magnitude of the reverse bias voltage, the isolation between adjacent elements may become insufficient, but in that case, it is sufficient to form a gap between the elements by etching the portion of the channel stop layer corresponding to the n+ layer. element isolation can be achieved.

FIG. 5 is a schematic diagram of an optical system of an embodiment in which the optical differential sensor of the present invention is applied to an image processing device.

In the figure, 35 and 36 are input images, 30 and 33 are polarizers, 31 and 32 are imaging lenses, 34 is a polarizing beam splitter, 20 is an analyzer array arranged two-dimensionally, and 21 is an optical 37 is an output image of an optical differential device in which differential sensors are arranged two-dimensionally.

In this embodiment, the light waves related to the two human-powered images 35, 36 are made into mutually orthogonal polarization components by a polarizer 30, 33, and are combined by a polarizing beam splitter via an imaging lens 31, 33. The combined image is then transferred to the analyzer array 2.
0 is selectively separated, and the optical difference device 21 obtains a difference signal for each pixel, thereby obtaining an output image 37.

FIG. 6 is an explanatory diagram showing the relationship between the analyzer array 20 and the optical difference device 21 in FIG. 5.

In Fig. 6, two two-dimensional human image signals 35.3
6 is multiplexed, and the polarization directions of all the light waves 22 and 23 are orthogonal. Reference numeral 21 denotes an optical differential device in which the aforementioned optical differential sensors are two-dimensionally arranged, and 20 denotes an analyzer array arranged on either side of the optical differential device. In this embodiment, analyzers with polarization axes in the same direction are arranged in sensor parts of the same polarity, and analyzers with polarization axes perpendicular to each other are arranged in sensor parts with different polarity. This makes it possible to receive two manually generated images 35 and 36 whose polarization directions are perpendicular to each other by photodetecting elements with different polarities, thereby obtaining a difference signal between the manually generated images 35 and 36 in 2-'). ing.

In FIG. 5, the method of reading out the manual image difference signal 37 from the optical difference device 21 is, for example, by sequentially switching the photodetecting elements corresponding to each pixel using a transistor or the like and taking out a serial signal according to the coordinates. Also good.

In the above embodiments, the manual method of separating light into two photodetecting elements with different polarities using multiplexing of orthogonal polarized light was shown. It may also be carried out using chemical separation technology or the like.

Further, when the human image is a color image, the object of the present invention can be similarly achieved by installing a wavelength selective filter such as a color mosaic filter in front of the optical difference device.

FIGS. 7 and 8 are explanatory diagrams of the operating principle of another embodiment of the optical differential sensor of the present invention. In FIG. 7, two tie-outs 40, 41, ie, two photodetecting elements 40, 41 are coupled so that their polarities are different from each other, and a capacitor 42 is provided at the output end. If we pay attention to the voltage V at the coupling point, a voltage V will be generated that is proportional to the difference in the light intensity of the light waves applied to the two photodetecting elements 40 and 41.

However, if the charge accumulation is small, that is, if the difference in the intensity of the light produced by the human power is large, the charge will be saturated as shown by the dotted line in FIG. In the case of photodetection using an energy integral type as shown in FIG. 7, the light waves applied to both photodetecting elements 40 and 41 may have different times. The detection voltage at this time is a value proportional to the light intensity difference Pntn -PAta (LA, '-8 is the pulse width of the two optical signals) manually applied to both photodetecting elements 40 and 41.

In this embodiment, the switch 43 is for resetting the differential signal, and a bipolar type, MOS type, etc. transistor can be used.

FIG. 9 is a schematic diagram of an optical system of an embodiment when the optical differential sensor shown in FIG. 7 is applied to an image processing device.

In the figure, 52 is a human image plane, 53a, 53b
are two human images. 51 is a polarization device whose polarization direction can be controlled, 50 is a condenser lens, 57 is an analyzer array, 55 is a light difference device, and 56 is an output image plane.
A, 56ft are two output images. Reference numeral 54 denotes a clock generation circuit which alternately rotates the polarization direction of the polarization device 51 by 90 degrees in response to a synchronization signal.

A polarizing device is constructed by, for example, providing a plurality of polarizing plates on a transparent disk, and driving the disk with a step motor or the like so that the polarization directions of the polarizing plates are orthogonal to each other in response to each step rotation of the disk. are doing.

In this embodiment, at time t-to, the polarization angle of the polarization device 51 is set to 0 degrees (relative value), and a manually-powered image 53b (broken line) is manually transmitted to the optical difference device 55 via an array 57 by light analysis. Next, at time 1=1o+Δt, the polarization angle of the polarization device 51 is set to 90 degrees (relative value), and a human image 5:]a (solid line) is similarly applied to the optical difference device 55. At this time, each of the manually input images 53a and 53b is manually input to the optical difference device 55 while being separated according to the polarization direction, thereby detecting the difference in light intensity between the two input images 53a and 53b as a voltage difference. The output voltage at this time can be represented, for example, as two positive and negative voltage contrast output images 568 and 56B as shown on the output image plane 56.

Therefore, from this, the time t=70 and the time t=to+Δ
It becomes possible to detect changes over time such as the movement of the image from time t.

The optical differential sensor in each of the above embodiments has a Schottky structure, an MO3 structure, in addition to a PN junction type or NP junction structure.
It may also be configured using a photodetector element such as a structure or a phototransistor structure.

(Effects of the Invention) According to the present invention, by integrally configuring two photodetecting elements with different polarities as described above, it is possible to obtain a differential signal between two image information in real time and with high precision. A differential sensor can be achieved.

In particular, by arranging optical differential sensors one-dimensionally or two-dimensionally, it is possible to easily obtain an intensity difference signal between two image information in real time, and the optical differential sensor can also be used as an energy storage type output format. If used, it can be applied as a light energy difference device, and can be applied, for example, to an image processing device that detects the movement of two images at different times.

[Brief explanation of the drawing]

1, 2, and 3 are explanatory diagrams of the operating principle of the optical differential sensor of the present invention, and Figures 4 (A) and (B) are explanatory diagrams of an embodiment of the configuration of the optical differential sensor of the present invention. , FIG. 5 is a schematic diagram of an optical system of an embodiment when applied to an image processing apparatus such as an optical differential sensor of the present invention, FIG. 6 is an explanatory diagram of a part of FIG. 5, and FIGS. 7 and 8 are An explanatory diagram of the operating principle of another embodiment of the optical differential sensor of the present invention, FIG. 9 is a schematic diagram of an optical system of an embodiment when the optical differential sensor shown in FIG. 7 is applied to an image processing device. . In the figure, 1.2.40.41 is a photodetecting element, 5
．． 6 is a light wave, 20.57 is an analyzer array, 21.55 is an optical difference device, 35.36.53a, 53b is a human image, 30.33 is a polarizer, 31.32 is a condensing lens, 3
4 is a polarizing beam splitter, 37.56 is an output image plane, 42 is a charge storage capacitor, 54 is a clock generation circuit, and 43 is a reset switch. Patent Applicant Canon Co., Ltd. Figure 1, Figure 1, Figure 1, + (A), Figure 0, Figure 5, Procedural Amendment (Form) February 18, 1985 2, Name of the invention Optical differential sensor 3, Amendment Relationship with the case of a person who does
) Canon Co., Ltd. Representative Ryuzo Kaku
Part 4. Agent's residence 301 Jiyugaoka, Belheim, 2-17-3 Okusawa, Setagaya-ku, Tokyo 158 (telephone 718-5614) 6. Contents of amendment

Claims (3)

[Claims] (1) An optical differential sensor characterized in that two photodetecting elements are constructed by joining their respective electrical output ends so that the polarities of the photoelectric characteristics of the photodetecting elements are different from each other. (2) The optical differential sensor according to claim 1, wherein analyzers having different polarization axes are arranged in front of the inputs of the two photodetecting elements. (3) The optical differential sensor according to claim 1, wherein optical filters having different wavelength selectivities are arranged in front of the inputs of the two photodetecting elements.