Object discriminating apparatus and method therefor
First Claim
1. An object determining apparatus comprising:
- image capturing means for capturing an image;
object detecting means for detecting an object from the image captured by said capturing means;
means for subjecting those points on the image of the object detected by said object detecting means, which have maximum and minimum values at least in x- and y-directions, to a reverse perspective transformation into a given plane in a 3-dimensional space;
means for calculating, on the basis of a ratio of an area defined by four points on the image to an area defined by four points after the reverse perspective transformation, a cross-sectional area of the object in a given plane after the reverse perspective transformation, from the area on the image; and
means for comparing a value of the area calculated by said calculating means with a predetermined area value registered in advance, thereby determining the object.
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Abstract
An object sensor outputs an obstacle detection signal in response to passing of an obstacle. A central control unit reads a 2-dimensional image from an imaging unit in response to the obstacle detection signal. A detection area is obtained by subtracting a background image prestored in a memory from the input 2-dimensional image. The detected image on a 2-dimensional plane is transformed into image data in a 3-dimensional space. The CCU computes the projection area of the image data on an arbitrary plane in the 3-dimensional space. The object is discriminated by comparing the computed projection area with the projection area based on the reference value of the object prestored in the memory.
87 Citations
7 Claims
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1. An object determining apparatus comprising:
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image capturing means for capturing an image; object detecting means for detecting an object from the image captured by said capturing means; means for subjecting those points on the image of the object detected by said object detecting means, which have maximum and minimum values at least in x- and y-directions, to a reverse perspective transformation into a given plane in a 3-dimensional space; means for calculating, on the basis of a ratio of an area defined by four points on the image to an area defined by four points after the reverse perspective transformation, a cross-sectional area of the object in a given plane after the reverse perspective transformation, from the area on the image; and means for comparing a value of the area calculated by said calculating means with a predetermined area value registered in advance, thereby determining the object. - View Dependent Claims (3, 4)
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2. A method of determining an object, comprising the steps of:
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capturing an image; detecting an object from the captured image; subjecting those points on the image of the detected object, which have maximum and minimum values at least in x- and y-directions, to a reverse perspective transformation into a given plane in a 3-dimensional space; calculating, on the basis of a ratio of an area defined by four points on the image to an area defined by four points after the reverse perspective transformation, a cross-sectional area of the object in a given plane after the reverse perspective transformation, from the area on the image; and comparing a value of the calculated area with a predetermined area value registered in advance, thereby determining the object. - View Dependent Claims (5, 6, 7)
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Specification