Image analysis – Applications – Manufacturing or product inspection
Reexamination Certificate
1999-05-25
2003-10-28
Patel, Jayanti K. (Department: 2625)
Image analysis
Applications
Manufacturing or product inspection
C382S209000, C382S266000, C348S087000
Reexamination Certificate
active
06640002
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image processing apparatus or an object inspecting apparatus which obtains information relating to an object by processing image data representing an image of the object taken by an image taking device, and to a recording medium on which an image-processing or object-inspecting control program is recorded.
2. Related Art Statement
An example of the above-indicated image processing apparatus is disclosed in U.S. Pat. No. 5,754,677. The prior image processing apparatus measures, by using a seek template and a measure template, a position, a rotation angle, and at-least one dimension of an object. The position of the object being image-processed is expressed in terms of the coordinates of a specific point of the object, such as the center point of the object, or an arbitrarily designated point of the object. The rotation angle of the object is expressed in terms of the angle of rotation of the object from its reference rotation position. The seek template includes a plurality of pairs of points. It is a general rule that when one of the two points of each pair out of the pairs is located inside an outline of the object and the other point of the each pair is located outside the outline, the processing apparatus judges that the object being image-processed is an object being sought by the seek template. To this end, the pairs of points defining the seek template are determined based on the shape of the outline of the object. However, in the case where it is known in advance that the position and/or rotation angle of the object may greatly vary, the processing apparatus repeatedly judges whether the object is an object being sought, while changing the position and/or rotation angle of the seek template. In this case, the processing apparatus produces a master seek template based on the outline of a reference object which has one or more reference dimensions and which takes reference position and rotation angle. Then, the processing apparatus produces various individual seek templates by changing the position and/or rotation angle of the master seek template, and virtually superposes each of the individual seek templates on a screen on which the image of the object is present. If any one of the individual seek templates satisfies the above-indicated rule, the processing apparatus judges that the object being image-processed is an object being sought. The object being image-processed or the object being sought may be a single, independent article as a whole, a portion of an article, or a projection, a hole, or a character present on an outer surface of an article. In the case where an object being sought has a simple shape, such as a quadrangle or a circle, a seek template including a small number of pairs of points is used. On the other hand, in the case where an object having a complex shape is sought, it is needed to use a seek template including a great number of pairs of points.
If the object being image-processed is judged as an object being sought, then the image processing apparatus measures, by using a measure template, the position, rotation angle, and/or dimensions of the object. In this connection, the object being image-processed that is judged as an object being sought is deemed as an object being measured. The image processing apparatus automatically produces the measure template based on the seek template with which the object being image-processed is judged as an object being sought. The simplest measure template is defined by a plurality of straight segments each of which connects between the two points of a corresponding one pair out of the pairs of points defining the seek template. As far as the present application is concerned, those straight segments are referred to as the “search lines”. The processing apparatus determines respective points at which the search lines intersect the outline of the object being measured. In the case where an optical characteristic (e.g., degree of lightness) of an image of the object differs from that of an image of the background of the object, the luminance of the two images significantly changes at the positions of the outline of the object. The positions where the luminance significantly changes will be referred as the “edge” of the object, and respective points where the search lines intersect the edge will be referred to as the “edge points”. That the luminance significantly changes at the edge of an object being measured means that the rate of change of the luminance is greater than a predetermined value at the edge. In many cases, the outline of an object being measured is determined as the edge of the object. In those cases, the image processing apparatus can measure the position, rotation angle, and/or dimensions of the object, by using the measure template, i.e., by obtaining the set of the edge points present on the outline of the object. In the case where an object being measured has a simple shape, such as a quadrangle or a circle, a measure template including a small number of search lines is used. On the other hand, in the case where an object having a complex shape is measured, it is needed to use a measure template including a great number of search lines. In addition, in many cases, the number of search lines included in a measure template is greater than the number of pairs of points included in a seek template.
However, an image of an object may have an edge at positions where an optical characteristic (e.g., color) of the image other than degree of lightness significantly changes. In the above description, it is assumed for easier understanding purposes only that the two points of each pair out of the pairs of points of a seek template are located inside and outside the outline of the object, respectively, and the search lines of a measure template intersect the outline of the object. In fact, the search lines have only to intersect the edge of the object, and the two points of each pair have only to be located on both sides of the edge, respectively. In the above description, it is also assumed for easier understanding purposes only that the image processing apparatus performs, one time, a measurement using a measure template. However, in many cases, the processing apparatus performs two or more measurements using respective measure templates. In those cases, after the processing apparatus performs one measurement using one measure template, the apparatus additionally produces a new measure template including a greater number of search lines, or a new measure template having a smaller positional error with respect to the object being measured, and performs a more accurate measurement using the new measure template.
As is apparent from the foregoing description, the image processing apparatus can quickly seek, using a seek template, an object and quickly measure, using a measure template, a position, a rotation angle, and/or one or more dimensions of the object, even if the position and/or rotation angle of the object may be greatly deviated from its expected position and rotation angle.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image processing apparatus or an object inspecting apparatus which further improves the above-described image processing apparatus.
It is another object of the present invention to provide a recording medium on which an image-processing control program or an object-inspecting control program is recorded.
The present invention provides an image processing apparatus, an object inspecting apparatus, and a recording medium which have one or more of the technical features that are described below in respective parenthesized sequential numbers (1) to (19). Any technical feature which includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to that technical feature. Thus, two or more of the following features may be combined, if appropriate. Each technical feature may be accompanied by a supplement
Chawan Sheela
Fuji Machine Mfg. Co. Ltd.
Oliff & Berridg,e PLC
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