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US 5,859,924 AGranted
Method and system for measuring object features
AssigneeRobotic Vision Systems, Inc.
InventorsKuo-Ching Liu, Chu-Kwo Liang, Jong-Kae Fwu, Chung-Po Huang
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Abstract
A system is provided that simultaneously gathers three-dimensional and two-dimensional data for use in inspecting objects such as chip carriers for defects. Specifically, a source laser beam is directed to an object and forms a spot at the point of impingement at a known X-Y position on the object. The laser beam is reflected at the spot and light reflected off-axially with respect to the source laser beam is detected by two position sensing detectors (PSDs). Simultaneous to detecting off-axially reflected light, retro-reflected light (i.e., the light reflected approximately co-axial with the source laser) is detected by a photo diode array.
Claims22
A method for determining at least one dimension of at least a portion of an object, comprising the steps of:
- a) scanning at least a portion of the object with a plurality of spots of light emitted by a light source, each of the plurality of spots of light being transmitted along a respective first path, each of the plurality of spots of light impinging the object at a respective X-Y coordinate;
- b) for each respective X-Y coordinate, detecting with a position sensing detector light reflected from the object along a respective second path spaced from the respective first path, the detected light impinging the position sensing detector at a respective position;
- c) for each respective X-Y coordinate, generating a respective first signal indicating the respective position;
- d) for each respective X-Y coordinate, determining a Z-coordinate as a function of the first respective signal;
- e) for each respective X-Y coordinate, and simultaneously with step b), detecting light retro-reflected from the object at the respective X-Y coordinate;
- f) for each respective X-Y coordinate, generating a respective second signal representing an intensity of the detected retro-reflected light;
- g) forming a two-dimensional image of at least a portion of the scanned portion of the object as a function of a plurality of the respective second signals;
- and
- h) determining at least one dimension of the object as a function of the two-dimensional image.
6 more elements
A method for determining dimensions of at least a portion of an object comprising the steps of:
- a) illuminating at least a portion of an object at a predetermined X-Y coordinate with a spot of light emitted by a light source, the spot of light being transmitted along a respective first path;
- b) detecting with a position sensing detector light reflected from the object along a respective second path spaced from the respective first path, the detected light impinging the position sensing detector at a respective position;
- c) generating a respective first signal indicating the respective position;
- d) simultaneously with step b), detecting light retro-reflected from the object at the predetermined X-Y coordinate;
- e) generating a respective second signal as a function of an intensity of the light detected in step d);
- f) repeating steps a)-e) for a plurality of different portions of the object at respective X-Y coordinates;
- g) forming a three-dimensional image of at least a portion of the object as a function of a plurality of the respective first signals;
- h) forming a two-dimensional image of at least a portion of the object as a function of the respective second signals;
- and
- i) determining at least one dimension of the object as a function of at least one of the two-dimensional image and the three-dimensional image.
7 more elements
A method for imaging an object comprising the steps of:
- a) scanning at least a portion of the object with a plurality of spots of light emitted by a light source, each of the spots of light being transmitted along a respective first path, each of the plurality of spots of light impinging the object at a respective X-Y coordinate;
- b) for each respective X-Y coordinate, detecting with a position sensing detector light reflected from the object along a respective second path spaced from the respective first path, the detected light impinging the position sensing detector at a respective position;
- c) for each respective X-Y coordinate, generating a respective first signal indicating the respective position;
- d) for each respective X-Y coordinate, determining a Z-coordinate as a function of the first respective signal;
- e) for each respective X-Y coordinate, and simultaneously with step b), detecting light retro-reflected from the object at the X-Y respective X-Y coordinate;
- f) for each respective X-Y coordinate, generating a respective second signal indicating a respective intensity of the detected retro-reflected light;
- and
- g) forming a two-dimensional image of the portion of the object as a function of a plurality of the respective second signals.
5 more elements
A system for imaging at least a portion of an object comprising:
- a light source for emitting a plurality of spots of light, each of the plurality of spots of light being transmitted along a respective first path to impinge the object at a respective X-Y coordinate;
- a first position sensing detector for detecting for each respective X-Y coordinate light reflected from the object along a respective second path spaced from the respective first path and impinging the first position sensing detector at a respective position, the first position sensing detector also for generating for each respective X-Y coordinate a respective first signal indicating the respective position;
- a photo sensitive device for detecting, simultaneously with the detection by the first position sensing detector, for each respective X-Y coordinate light retro-reflected from the object at the respective X-Y coordinate and generating for each respective X-Y coordinate a respective second signal representing an intensity of the detected retro-reflected light;
- and
- a processor for generating a three-dimensional image of the at least a portion of the object as a function of a plurality of the respective first signals, the processor also for receiving a plurality of the respective second signals and generating a two-dimensional image of the portion of the object as a function of the plurality of the respective second signals.
2 more elements
An optical measurement system comprising:
- a light source for emitting a plurality of spots of light, each of the plurality of spots of light being transmitted along a respective first path to impinge the object at a respective X-Y coordinate;
- a position sensing detector for detecting for each respective X-Y coordinate light reflected from the object along a respective second path spaced from the respective first path and impinging the first position sensing detector at a respective position, the first position sensing detector also for generating for each respective X-Y coordinate a respective first signal indicating the respective position;
- a photo sensitive device for detecting, simultaneously with the detection by the position sensing detector, for each X-Y coordinate light retro-reflected from the object at the respective X-Y coordinate and for generating for each respective X-Y coordinate a respective second signal representing an intensity of the detected retro-reflected light;
- and
- a processor for receiving each respective first signal and generating a three-dimensional image of at least a portion of the object as a function of a plurality of the respective first signals, the processor also for receiving each second signal and for generating a two-dimensional image of at least a portion of the object as a function of a plurality of the respective second signals, the processor further for determining at least one dimension of the object based on at least one of the two-dimensional image and the three-dimensional image.
2 more elements
Dependencies are inferred from the claim text.