 Method and apparatus of pattern recognition |
| In view of the foregoing, the first object of the present invention is to obtain a pattern ... |
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| Apparatus for and a method of communicating between a camera and external equipment |
| Accordingly, it is an object of the present invention to provide a camera which performs data ... |
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| Method and apparatus to detect capillary indentations |
| OF THE INVENTION In FIG. 1, a system incorporating the present invention is shown. The system ... |
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| Vision coprocessing |
| We claim: 1. A digital image processing system including A. bus means for carrying control, data ... |
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| Digital image capture control |
| It is therefore an object of the invention to provide an intuitive, object-oriented user interface ... |
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| Continuous diffuse illumination method and apparatus |
| The practice of the concepts of the invention are primarily utilized in machine vision applications ... |
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| Inspecting apparatus of mounted component |
| The object of the present invention is therefore to provide an inspecting apparatus which can ... |
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| Method and apparatus for high speed identification of objects having an identifying feature |
| The invention is directed to a method and apparatus for identifying an object having an identifying ... |
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| Image rotating method for locating bond pads in an image |
| The foregoing objects are attained by the invention which provides a method for operating a digital ... |
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Solder joint locator
| Details |
Inventors: Bushroe, Michael W.;
Assignee: Hughes Aircraft Company (Los Angeles, CA)
Primary Examiner: Moore; David K.
Assistant Examiner: Stellrecht; Barry
Attorney, Agent or Firm: Heald; R. M., Brown; C. D., Denson-Low; W. K.
A system (82) and method for locating features in an image. In the preferred embodiments, the present invention accepts as input a tilted view X-ray image of a PC board (10), as well as expected locations of solder joints (18) in the PC board (10). The present invention then determines the actual center locations (32) of these solder joints (18) by defining windows within the image and checking individual areas within the window, to see if they fall below a predetermined threshold. In addition, the system (82) determines if these pixels are connected to other pixels that have been previously determined to be part of the solder joint (18). Finally, the system (82) determines the center of the group of pixels determined to be part of the solder joint and displays the coordinate location of this center. |
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DETAILED DESCRIPTION Pursuant to the present invention, a method and system is provided for automatically detecting features in an image.
The system comprises a means for measuring and storing the intensity of pixels in the image, and a means for defining a window within the image.
This window is selected so that the center of the window is coincident with the expected center of the feature to be located.
The system also includes a means for determining which pixels in the window are below a predetermined upper threshold of intensity.
The system also determines if pixels found below the threshold are connected to the center pixel and labels those pixels as feature pixels.
Also, the system determines if pixels found to below the threshold are connected to any pixels previously labeled feature pixels, and labels those pixels also feature pixels.
Finally, the system determines the center of the group of feature pixels and displays the coordinate location of this center.
To further improve the ability to recognize desired features, in accordance with a second embodiment of the present invention, there is provided a means for adaptively setting the threshold for each window that is analyzed.
This is done by providing a means for measuring the intensity of a solder strip of known thickness in the image.
The system then can set a threshold that is equal to this measured intensity of the solder strip.
The system further measures the intensity of several pixels in the vicinity of the center pixel and determine the darkest of these pixels.
The system then will determine if this darkest pixel is lighter than the previously set threshold.
If it is, the system stops because this would mean that the feature falls outside the acceptable range.
For example, this could mean a defective solder joint.
On the other hand, if the darkest pixel is not lighter than the threshold, then a new threshold is set that is equal to the value of this darkest pixel plus a predefined margin.
As a result, the threshold used by the system is adapted for each window to be closely calibrated to the particular intensity of the feature to be analyzed
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Image Analysis 
