JPH0810131B2 - Solid-state imaging camera for pattern recognition - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a solid-state image pickup camera for pattern recognition, and more particularly, to a solid-state image pickup camera used for recognizing a displacement amount of a linear pattern image with respect to reference coordinates. The present invention relates to an imaging device.

[Technical background of the invention]

For example, in an unmanned manufacturing site or warehouse, the guideline 1 displayed on the floor as shown in FIG. 1 is automatically monitored by the pattern recognition device mounted on the automated guided vehicle 2 while monitoring the traveling direction. A feedback control system may be adopted. The pattern recognition device performs pattern recognition processing on an output signal obtained by imaging the guideline 1 with a solid-state imaging camera (including an imaging optical system and a solid-state imaging device) 3. In this type of conventional solid-state image pickup camera, a solid-state image pickup device (area sensor) in which pixels 4 are arranged two-dimensionally is used as shown in FIG. 2, and the image pickup surface of this area sensor is used. A subject image (straight line pattern image 5) is formed on the upper side by the image forming optical system as shown in the figure. Then, the recognition of the linear pattern image 5 is performed by recognizing the displacement amount of the linear pattern image 5 at the x, y coordinates (reference coordinates) with the center point of the imaging surface as the origin, that is, the shortest distance (deviation from the origin to the linear pattern image 5). ) D
And the angle (tilt) θ at which the linear pattern image 5 intersects with the x-axis can be obtained. In this case, the conventional pattern recognition apparatus is configured to temporarily store the imaged output of the area sensor in the image memory, read the stored data, and perform the arithmetic processing for pattern recognition.

[Problems of background technology]

However, the conventional pattern recognition device as described above,
Since the area sensor having a large number of pixels and the image memory having a large storage capacity are required, the system price becomes expensive.
In other words, considering the ratio between the pattern recognition ability of the subject and the price, it is effective when the subject pattern is unknown, but when the subject pattern is known, the above capacity-to-price ratio is necessary. The sushi is not good either.

Further, since the above-mentioned conventional device uses the area sensor, the time required for reading the output signal, writing / reading the image memory, and calculation processing becomes long, which makes it difficult to speed up pattern recognition. Moreover, since the amount of data for arithmetic processing is large, the configuration of the arithmetic circuit and its peripheral circuits becomes complicated and expensive.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and when the subject is a linear pattern, it is possible to perform pattern imaging for simplifying and accelerating the recognition process of the displacement amount of the subject pattern image with respect to the reference coordinates. The present invention provides a solid-state imaging camera for pattern recognition, which can reduce the system price of the pattern recognition device and speed up the recognition process.

[Outline of Invention]

The solid-state imaging camera of the present invention is a signal for reading out a time-series output signal of a level corresponding to incident light intensity in a first pixel group in which a plurality of pixels are linearly arranged and in each pixel of the first pixel group. A first solid-state line sensor having an output means, a second pixel group formed in parallel with the first pixel group of the first solid-state line sensor, and incident light intensity at each pixel of the second pixel group. Second solid-state line sensor having a signal output means for reading out an output signal of a level according to the time series, and a linear pattern which is a subject image in a state of crossing each pixel group of the first and second solid-state line sensors. And an image forming optical system for forming an image.

Further, the distance in the first direction from the position of the pixel on which the linear pattern image is formed in the first pixel group to one end of the first pixel group is x1, and the line in the second pixel group is The distance from the position of the pixel on which the pattern image is formed to the other end of the second pixel group in the direction opposite to the first direction is x2, and the first from the one end to the other end, When the distance parallel to the second solid line sensor is X and the distance between the first pixel group and the second pixel group is l, the distance from the first pixel group and the second pixel group is Of the linear pattern image of The first recognizing means for recognizing the linear pattern image based on the relationship between the first recognizing means and the first pixel group, and at least one of the linear pattern image deviation amount y2 from the second pixel group. It is characterized by comprising a second recognition means for recognizing based on the relation of y1 = x1 sin θ y2 = x2 sin θ.

Example of Invention

An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 3, 31 and 32 are first and second pixel groups in which a plurality of pixels (photoelectric conversion elements) P _{1 to} P _N and P ₁ ′ to P _N ′ are arranged linearly and are parallel to each other. is there. The two pixel groups 31 and 32 are provided on the same semiconductor chip, for example, and the pixels P _{1 to} P _N and P ₁ ′ to P _N ′ are arranged on the chip from the pixel groups 31 and 32, respectively. A signal reading means (not shown) is provided for reading signals according to the intensity of incident light in time series in the order of the pixels P _{1 to} P _{N and} the order of the pixels P ₁ ′ to P _N ′. Therefore, two line sensors are provided in parallel. The signal reading means transfers the signal charge by photoelectric conversion of each pixel to the charge transfer register, transfers each charge sequentially by this register, and the amount of the transferred charge, as in a normal line sensor. Is converted into a voltage level and output. In this case, charge transfer register or output circuit
The line sensors may be shared. Further, an image forming optical system (not shown) for forming a subject image at a predetermined magnification or scale is provided on the image pickup surface having the pixel groups 31, 32.

Next, regarding pattern recognition using the above solid-state imaging camera, for example, as shown in FIG. 3, the linear pattern image 33 shows the pixels P _{m of} the first pixel group 31 and the pixels of the second pixel group 32.
Description will be made assuming a case where an image is formed so as to cross P _n ′.
Here, the distance between the two pixel groups 31 and 32 is 1, the inclination of the linear pattern image 33 (the angle intersecting with the pixel groups 31 and 32) is θ (radian), and the end of the first pixel group 31 (pixel P The shortest distance between the _N side) and the linear pattern image 33 (from the above end to the linear pattern image 33
The vertical length of the vertical line) is represented by y ₁ , and the shortest distance between the starting end (pixel P ₁ ′ side) of the second pixel group 32 and the linear pattern image 33 is represented by y ₂ . Geometrically expressing these relationships,
As shown in the figure. Here, x ₁ is the length between the starting end P _N of the first pixel group 31 and the imaging pixel P _m , and x ₂ is the starting end P ₁ ′ of the second pixel group 32 and the imaging pixel P _m. a length between _n ′ and x
Is the interval in the pixel group length direction between the pixels P _m and P _n ′,
The total length of each of the pixel groups 31 and 32 is represented by X. Then, as can be seen from FIG. 4, the following equation holds.

x _i sin θ = y _i (i = 1,2) (1) X = x ₁ + x ₂ + x (3) When the pixel pitch is represented by Δx, from the above equation (2) Next to Therefore, if the number N of pixels in each of the pixel groups 31 and 32 and the number (address) information m, n representing the position in the pixel group of the pixels P _m and P _n ′ formed by the linear pattern image 33 are known, solid-state imaging is performed. Linear pattern image 33 with respect to the reference coordinates on the imaging surface of the device
The deviation amount (y ₁ , y ₂ ) and the inclination amount (θ) of the above equation (4),
It can be easily obtained from (5) and (6). In this case, the output signal of the image pickup device is, as shown in FIG.
In the output signal of 2, the output levels of the image forming pixels P _m and P _n ′ are significantly different from the output levels of the other pixels (the signal level is large in this example). Information can be detected. If the linear pattern image 33 has a large width and the signal output levels of not only the pixels P _m and P _n ′ but also the pixels adjacent thereto are large, the pixel P _m
High-level output signal group and pixel including the output signal of
The signal processing may be performed so as to detect the address information of the pixel having the peak level in each of the high-level output signal groups including the P _n ′ output signal.

The solid-state image pickup camera of the above embodiment forms a linear pattern image so as to cross a pixel group of two columns in which a plurality of pixels are arranged in a straight line in parallel with each other. By detecting the specific pixel on which the linear pattern image is formed from the characteristics of the above, the inclination amount θ and the deviation amounts y ₁ and y _{2 of the} linear pattern image are calculated by the above equations (4), (5) and (6). Can be easily recognized. In addition, the solid-state imaging device used has a smaller number of pixels than the area sensor of the conventional example, and the signal output means can perform the same driving and signal processing as those of the conventional line sensor, and can be realized at low cost. is there. Moreover, in order to recognize the displacement amount of the known straight line pattern, it is sufficient to perform the level determination processing and the arithmetic processing of the imaging output signal, and the image memory required in the conventional example can be omitted.
The circuit for performing the calculation processes of (5) and (6) is also simplified, and the system cost of the pattern recognition device can be reduced and the pattern image displacement amount recognition process can be speeded up.

The present invention is not limited to the above embodiment,
Various modifications can be made. The two pixel groups are formed on different chips instead of the same chip, that is, two line sensors are formed on different chips and each line sensor is arranged in parallel. Good. In this case, an imaging optical system may be provided for each line sensor as needed.

Further, it goes without saying that the camera of the present invention can be used by being mounted on the automatic guided vehicle described above with reference to FIG.
Its application range is wide.

〔The invention's effect〕

According to the solid-state imaging camera for pattern recognition of the present invention as described above, when the subject is a straight line pattern, in order to simplify and speed up the process of recognizing the displacement amount of the subject pattern image with respect to the reference coordinates on the imaging surface. It is possible to image the pattern, and it is possible to reduce the system price of the pattern recognition device and speed up the recognition process.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of use of a solid-state image pickup camera for pattern recognition, FIG. 2 is a diagram showing pixel arrangement on an image pickup surface of a conventional solid-state image pickup camera for pattern recognition, and FIG. 3 is a diagram for pattern recognition of the present invention. FIG. 4 is a diagram showing an example of a pixel arrangement of a solid-state image pickup device in one embodiment of the solid-state image pickup camera, FIG. 4 is a diagram for explaining the relationship between the pixel arrangement of FIG. 3 and a subject pattern image, and FIG. FIG. 6 is a waveform diagram showing an imaging output signal corresponding to the subject pattern image of FIG. 4. P _{1 to} P _N , P ₁ ′ to P _N ′ Pixel, 31, 32 …… Pixel group, 33 ……
Straight pattern image.

Claims (5)

[Claims] 1. A first pixel group in which a plurality of pixels are linearly arranged, and a signal output means for time-sequentially reading out an output signal of a level corresponding to the incident light intensity in each pixel of the first pixel group. A first solid-state line sensor having the second solid-state line sensor, a second pixel group formed in parallel with the first pixel group of the first solid-state line sensor, and an incident light intensity at each pixel of the second pixel group. A second solid-state line sensor having a signal output means for reading output signals of different levels in time series, and a subject image in a state of crossing each pixel group of the first solid-state line sensor and the second solid-state line sensor. An image forming optical system for forming a linear pattern image, and a first image pickup device from a position of a pixel on which the linear pattern image is formed in the first pixel group to one end of the first pixel group.
The distance along the direction is x1, and from the position of the pixel on which the linear pattern image is formed in the second pixel group to the other end of the second pixel group, the direction is opposite to the first direction. The distance
x2, the first from the one end to the other end,
When the distance parallel to the second solid line sensor is X and the distance between the first pixel group and the second pixel group is l, the first pixel group and the second pixel The inclination amount θ of the linear pattern image from the group is And a displacement amount y of the linear pattern image from the first pixel group.
1 and second recognizing means for recognizing at least one of the displacement amounts y2 of the linear pattern images from the second pixel group based on the relationship of y1 = x1 sin θ y2 = x2 sin θ. Characteristic solid-state imaging camera for pattern recognition. 2. When the pixel pitch of each of the first and second pixel groups is Δx and the number of pixels in the first pixel group is N,
x1 is recognized based on the relationship of (N−m) × Δx (m is the number information indicating the position of the pixel on which the linear pattern image is formed in the first pixel group), and x2 is n × The recognition according to claim 1, wherein the recognition is performed based on a relationship of Δx (n is number information indicating a position of a pixel on which a linear pattern image is formed in the second pixel group). Solid-state imaging camera for pattern recognition. 3. The first solid line sensor and the second solid line sensor are respectively provided on the same semiconductor chip, and a linear pattern which is a subject image in a state of crossing each pixel group of these solid line sensors. The solid-state image pickup camera for pattern recognition according to claim 1, wherein an image-forming optical system for forming an image is shared by the respective solid-state line sensors. 4. The first solid-state line sensor and the second solid-state line sensor are provided on different semiconductor chips, and a linear pattern which is a subject image in a state of crossing each pixel group of these solid-state line sensors. The solid-state imaging camera for pattern recognition according to claim 1, wherein an imaging optical system for forming an image is provided for each solid line. 5. The signal output means is shared by the first solid-state line sensor and the second solid-state line sensor, according to any one of claims 1 and 2. The solid-state imaging camera for pattern recognition according to the item.