Spot Detector

The Spot Detector module provides several configuration options for detecting spots/dots within an image. Unlike the corner detector modules, the Spot Detector module will identify the middle of a spot instead of its edges. The provided parameters allow you to specify what types of spots to identify aswell as how large and strong the spots need to be with respect to the background in order to be identified.



1. Max Size - Specifies the largest spot size that will be detected (its diameter)

2. Min Size - Specifies the smallest spot size that will be detected (lowest is 3). Together with the Max size this specifies the search size range that will be analyzed. Decreasing this size range will increase performance of this module.

3. Isolation - Defines how closely spots can be. If two spots are closer than the number of pixels specified in the isolation parameter the less stronger spot will be removed.

4. Strength - Defines how strong the spot needs to be in order to be identified. This is loosely related to the contrast of the depression (black dot) or elevation (white dot) and its surrounding area. The higher this contrast the more 'strength' a dot has.

5. Circular Threshold - Because many lines may have slight bumps in them that can be strongly identified as dots, the circular threshold parameter defines how much variation the circular border of the dot can be before being identified. This ensures that a dot is truly disconnected from other parts of the image. Note the image on the right that shows 2 potential spots with differing circularity threshold. Setting the threshold to 200 would eliminate the line segment.

6. Light Spots/Dark Spots - Select which type of dot you want to detect.

7. Appearance - Select how you'd like the results to be displayed.

8. Display As Annotation - Select if you want the results to be draw after all processing has been completed. If this is NOT selected then the next module in the processing pipeline will see the graphic as if it were part of the image and process it accordingly.


SourceSpot Detector
Note that dots near image edges may not be detected due to max window size.


SPOT_POINT_COUNT - number of detected spots
SPOT_POINTS - array of x, y coordinates of each spot

See Also

Laser Spot
Harris Corners
Surface Texture

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