JPH0314187A - Image input device - Google Patents

Abstract

PURPOSE:To simply obtain the detection characteristic of an ON center type by providing an optical transmission member in which retracting power of the center element side is larger than that of the peripheral element side on the surface of an photo receptor layer, and placing an optical diffusion member in an image forming position in front of an optical path from the optical transmission member. CONSTITUTION:A photo receptor layer 11 in which a pair of optical receiving elements 15 of a double circular structure consisting of a center element 14 and a peripheral element 13 are arranged two-dimensionally is provided, an optical transmission member 17 which is placed on the surface of the photo receptor layer 11 and in which refracting power of the center element 14 side is larger than that of the peripheral element 13 side is provided, and an optical diffusion member 12 is placed in an image forming position in front of an optical path from the optical transmission member 17. In such a way, as for the receiving area on the optical diffusion member 12, the peripheral element 13 is larger than the center element 14, and by amplifying outputs of these center element 14 and peripheral element 13 in a prescribed ratio and taking a difference, etc., the detection characteristic of an ON center type can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an image input device applicable to artificial vision for extracting edge information of an image.

2. Description of the Related Art In recent years, image input devices have been devised that imitate the visual function of living organisms and extract edge information in order to determine the shape of an image.

Therefore, as a conventional example of such an image input device, the device disclosed in Japanese Patent Publication No. 50-34'901 is referred to as No. 8.
This will be explained based on FIGS. 1 to 10. This image input device 1 is a photoreceptor, which corresponds to the retinal photoreceptor cells of the eyeball, in which photoelectric conversion elements 3, which are light receiving elements, are two-dimensionally arranged on the optical axis of an imaging lens 2, which corresponds to the crystalline lens of the eyeball. Layer 4 is arranged. Further, a threshold element layer 6 is provided in which threshold elements 5 having nonlinear characteristics connected to a certain number of the photoelectric conversion elements 3 are two-dimensionally arranged. The line segment direction detection layer 7 connected to this threshold element M6, for example, connects line segment direction detection elements 8 in each direction that are connected to a certain number of the threshold elements 5 and detect a specific amount of inclination α. Layers arranged two-dimensionally (
(not shown), and is formed by a three-dimensional structure in which these two-dimensional layers are sequentially connected.

In addition, the above-mentioned elements 5 and 8 of each N6 and 7 are connected to the previous N4 and
6, so that their receiving areas overlap.

In this configuration, in the image input device 1, a projected image (not shown) of the read image 9 is formed on the photoreceptor layer 4 by the imaging lens 2, and each photoelectric conversion element is The contrast of the projected image is detected from the output value of step 3.

An example of a detection mechanism that operates in this manner will be explained based on FIGS. 9 and 10. First, − threshold elements 5
When the receiving area of is composed of N photoelectric conversion elements 31 to 3n arranged in a matrix, for example, one photoelectric conversion element 3 located at the center of the arrangement and each photoelectric conversion element 3 located around this is connected to the threshold element S via a weighting coefficient circuit (not shown) so that the output value becomes O when the entire receiving area receives light. Therefore, each photoelectric conversion element 3. If the output value of ~3n is U~Un and the weighting coefficient at the time of input is C3~Cn, then the human power value Ni to this threshold element 5 is
j becomes Nj, j=C, U, +C2U2+-CnUn.

Note that these weighting coefficients C0 to Cn are set by, for example, providing an inverter circuit, a resistor, or the like between each of the photoelectric conversion elements 3 to 3D and the threshold element 5. There,
As illustrated in FIG. 10, the detection characteristics of the threshold element 5 are of an on-center type in which the output of the photoelectric conversion element 3 located at the center of the receiving area is treated as positive, and the output of the surrounding photoelectric conversion elements 3 is treated as negative. .

Further, the output value Ujj of the threshold element 5 is outputted twice according to the function Uij=I fence+1'=B+hl. However, e is the photoelectric conversion element 3 at the center position.
h is the total input value from the surrounding photoelectric conversion elements 3 to the threshold element 5. Therefore, the edge of the projected image exists within the receiving area formed by the photoelectric conversion elements 31 to 3n; i and its threshold element 5 output a positive output value U1j according to the above-mentioned function. In other words, when the projected image covers the central photoelectric conversion element 3, the output value Ujj of the threshold element 5 is large, and when the projected image is projected on the side of the receiving area, the output value Uij of the threshold element 5 is large. is small. Note that the output value Uij of the threshold element 5 is O in a receiving area on which no projection image is projected or a receiving area completely covered.

Then, these output values U1j are input to the line segment direction detection layer 7, and the line segment direction detection elements 8 corresponding to each line segment of the projected image are inputted to the line segment direction detection layer 7.
Thus, the amount of inclination of the line segment existing at the position (x, y) on the photoreceptor N4 is detected.

Problems to be Solved by the Invention In the above-mentioned image input device 1, etc., weighting coefficients C□~ are applied to the plurality of photoelectric conversion elements 31 to 3n forming one receiving area.
By setting Cn, on-centered detection characteristics are obtained. However, in order to set the weighting coefficients C□ to Cn, it is necessary to provide a weighting coefficient circuit consisting of a resistor, an inverter circuit, etc. for each photoelectric conversion element 3, and a large number of circuits are required for one receiving area. Since it is necessary to provide parts etc., the photoreceptor layer 4
The circuit configuration of the threshold element layer 6 and the threshold element layer 6 is extremely complicated, and the productivity of the device is low.

Means for Solving the Problem A photoreceptor layer is provided in which a large number of photoreceptive elements are arranged two-dimensionally, and outputs from each of the plurality of photoreceptor elements are received to generate an output equal to a function of a weighted sum. In an image input device provided with a threshold element layer in which threshold elements are arranged two-dimensionally, a photoreceptor in which a double-circular photoreceptor element set consisting of a center element and a peripheral element is arranged two-dimensionally. A light transmitting member is provided on the surface of the photoreceptor layer and has a larger refractive power on the central element side than on the peripheral element side, and a light diffusing member is provided at an image forming position in front of the optical path of the light transmitting member. Deploy.

A photoreceptor layer is provided in which a double circular photoreceptor element set consisting of an action center element and a peripheral element is arranged two-dimensionally, and the central element is arranged on the surface of this photoreceptor layer from the peripheral element side. By providing a light transmitting member 4 with a large refractive power on the side and arranging a light diffusing member at an image forming position in front of the optical path from this light transmitting member, the receiving area on the light diffusing member is such that the surrounding elements are the center element. By amplifying the outputs of the center element and the surrounding elements by a predetermined ratio and taking the difference, it is possible to easily obtain an on-center type detection characteristic.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. Note that the same parts as those in the image input device 1 described above are given the same names and symbols, and the description thereof will be omitted. First, in the image input device 10 of this embodiment, the light diffusing member 12 is disposed between the imaging lens 2 and the photoreceptor layer 11. On the other hand, the photoreceptor Ji11.1 has an annular surrounding element 1.
A photoreceptor element set 1-5 having a photoelectric conversion function and formed in a double circular structure by a central element 14 and a photoreceptor element 3 are two-dimensionally arranged. In this image input device ff1lo,
A light transmitting member 17 in which a convex lens portion 16 is formed on each front surface of the central element 14 is attached to the surface of the photoreceptor layer 11. Further, the photoreceptor element set 15 is connected to the threshold element 5 via amplifiers 18 and 19 and a differential amplifier 20, which are connected for each element]3.1/l.

With such a configuration, the image input device 10 extracts edge information of the read image 9 in substantially the same manner as the image input device 1 described above. Here, in this image input device 10, the light diffusing member 12 is arranged on the optical path leading to the photoreceptor layer].
A convex lens portion 6 is formed only on the front surface of the central element 14 surrounded by the annular peripheral element 3. Therefore, in this image input device 10, the projection light of the read image 9 formed on the light diffusing member 12 and diffused is condensed by the convex lens section 16 and received by the central element 14,
In other parts, the light passes through the light transmitting member], 7 and is received by the surrounding element 13. In other words, the directivity of each light-receiving element set 15 with respect to incident light is higher than that of the central element 1 compared to the surrounding elements 13.
4 is higher.

Therefore, the detection characteristics of each photoreceptor element set 15 when a minute light spot moves on the light diffusing member 12 will be described below. First, as illustrated in FIG. 3(a), the output of the central element 14 is large when the light spot is located approximately at the center of the photoreceptor element set 15, and drops sharply when it deviates from this point. . In addition, the output of the peripheral element 13 in the same case as "double" is the third
As illustrated in Figure (b), when the light spot is located approximately at the center of the photoreceptor element set 15, it is approximately the thickest, and as it deviates from this point, it gradually decreases.

In this image input device 10, the outputs of the peripheral element 13 and the central element 14 exhibiting the characteristics described above are transmitted to the amplifier 1.
8.19 to a predetermined ratio and the difference is taken by the differential amplifier 20, it is possible to easily obtain an on-centered detection characteristic as illustrated in FIG. 3(O).

Note that in the image input device 10 of this embodiment, each central element 1
A flat light transmitting member 17 in which a convex lens portion 16 is formed every 4 is attached to the surface of the photoreceptor [11].
The present invention is not limited to this, but the central element 14
It is sufficient that the refractive power for incident light is greater on the central element 14 side than on the peripheral element 13 side so that the directivity of the central element 14 is higher than that of the peripheral element 13. That is, for example, a convex lens formed separately may be attached to each central element 14, a concave lens formed separately may be attached to each peripheral element 13, or a front surface of the central element 14 may be convex. A light transmitting member having a concave front surface of the peripheral element is provided, and a convex lens-shaped light transmitting member having a larger refractive power on the center element 14 side than on the peripheral element 13 side is provided for each light receiving element group 5. Alternatively, a concave lens-shaped light transmitting member having a larger negative refractive power on the peripheral element 13 side than on the central element 14 side may be provided for each light receiving element set 15.

Furthermore, in this image input device 10, since each photoreceptor element set 15 is formed of two elements, the peripheral element 13 and the center element 14, wiring to each threshold element 5 is simple. moreover,
In this image input device 10, a light diffusing member 12 that diffuses the projected image of the read image 9 is arranged on the optical path leading to the photoreceptor M11. By making it flexible, the area of the projected image that is received here can be adjusted. In this case, the photoreceptor element set 15
Since the detection range of the photoreceptor layer J] is expanded or contracted, the size of the receiving area of the photoreceptor layer J can be changed. Furthermore, each element 1 such as ``double series''
It is also conceivable to form the threshold element 5 and the like along with 3.14 on a single substrate, and in this case, the productivity of the image input device can be further improved.

A second embodiment of the present invention will now be described with reference to FIGS. 4 and 5. This image input device 21 includes peripheral elements 1
A light transmitting member 24 made of a Fresnel lens is attached to the surface of the photoreceptor N11, with the front surface 23 of the central element 14 having a larger refractive power than the front surface 22 of the center element 14.

In such a configuration, this image input device 21:
The projected light of the read image 9 formed and diffused on the light diffusing member 12 is strongly focused on the front surface 23 and received by the central element 14 , and is weakly focused on the front surface 22 and then received on the peripheral element 13 . Light is received. Then, in the same manner as the image input device 10 described above, the edge information of the read image 9 is extracted by obtaining the on-center type characteristic.

Note that in the image input device 21 of this embodiment, the light transmitting member 2
4 is formed of a Fresnel lens, it is easy to set a large difference in directivity between the peripheral element 13 and the central element 14 without increasing the thickness of the device.

Furthermore, a third embodiment of the present invention will be described based on FIGS. 6 and 7. This image input device 25 includes a central element 1
A light transmitting member 27 having a gradient index lens 26 formed on the front surface of the photoreceptor layer 11 is attached to the surface of the photoreceptor layer 11 .

In this configuration, this image input device @25 has the following functions:
The projected light of the read image 9 that has been imaged and diffused on the light diffusing member 12 is focused by the gradient index lens 26 and received by the central element 14, and the light transmitting member 27 is used in other parts. The light is transmitted and received by the peripheral element 13. Then, edge information of the read image 9 is extracted in the same manner as in the image input device 10° 21 described above.

Month 2 Effects of the Invention As described above, the present invention provides a photoreceptor layer in which a large number of photoreceptive elements are arranged two-dimensionally, receives the outputs from the plurality of photoreceptive elements, and calculates a weighted sum. In an image input device equipped with a threshold element layer in which threshold elements that generate an output equal to a function are arranged two-dimensionally, a photoreceptor element set with a double circular structure consisting of a central element and peripheral elements is arranged two-dimensionally. An arrayed photoreceptor layer is provided, and a light transmitting part is provided on the surface of the photoreceptor layer and has a larger refractive power on the side of the central element than on the side of the surrounding elements, and the image formation in front of the optical path from the light transmitting member is provided. By arranging the light diffusing member at the image position, a crosstalk area with the adjacent photoreceptor element set is obtained, and the receiving area on the light diffusing member is such that the surrounding elements are larger than the central element, and the surrounding elements are larger than the central element. By amplifying the outputs of the element and the surrounding elements at a predetermined ratio and taking the difference, it is possible to easily obtain on-center detection characteristics, so the circuit structure is simple, and each photoreceptor element set is It is made up of two light-receiving elements with a double circular structure, so
The structure of the light-receiving section is also simple, wiring is simple, and an image input device with high productivity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a first embodiment of the present invention, FIG. 2 is an explanatory view showing the structure of a light-receiving element set and a light-transmitting member, and FIG.
Figure (a) is a characteristic diagram showing the output of the central element of the photoreceptor set, Figure 3 (b) is a characteristic diagram showing the output of the peripheral elements of the photoreceptor set, and Figure 3 (c) is the characteristic diagram of the photoreceptor element. FIG. 4 is a vertical cross-sectional side view showing the second embodiment of the present invention, and FIG. 5 is a diagram showing the structure of the light-receiving element set and the light-transmitting member. 6 is a longitudinal sectional side view showing the third embodiment of the present invention, FIG. 7 is an explanatory view showing the structure of the light-receiving element set and the light-transmitting member, and FIG. 8 is the structure of the conventional example. FIG. 9 is an explanatory diagram of the connection state between the photoreceptor element set of the photoreceptor layer and the threshold element of the threshold element layer, and FIG. 10 is an explanatory diagram of the formation of an on-center type detection characteristic. 5... Threshold element, 10, 21.25... Image input device,
1]・Photoreceptor layer, 12・・Light diffusion area, 13・Surrounding element, 4 Center element, 15・・Photoreceptor element set, 17.
24.27...Light transmitting member applicant Rico Co., Ltd.

Claims (1)

[Claims] A photoreceptor layer is provided in which a plurality of photoreceptor elements are arranged two-dimensionally, and a threshold element that receives outputs from the plurality of photoreceptor elements and generates an output equal to a function of a weighted sum is provided. In an image input device that includes a threshold element layer arranged in a circular pattern and extracts edge information corresponding to an image that is optically input to the photoreceptor layer, the photoreceptor layer has a double circular structure consisting of a center element and a peripheral element. A photoreceptor layer in which element sets are arranged two-dimensionally is provided, a light-transmitting member is provided on the surface of the photoreceptor layer and has a larger refractive power on the central element side than on the peripheral element side, and this light-transmitting member is provided. An image input device characterized in that a light diffusing member is disposed at an image forming position further forward in the optical path.