Ring Corner

The Ring Corner module is a point feature module that identifies corners based on how the surrounding pixels compare with the center pixel. This is functionally similar to Edward Rosten's FAST corner detector which has been known to be one of the fastest corner detectors to date.

The corner detector provides a way to identify points within an image that are hopefully repeatable in successive frames. As corners are scale, translation and rotationally invariant they provide valuable keypoints that can be used to compare one image with another

Interface

Instructions

1. Corner Threshold - defines what range of pixel values are considered equal. For example, a pixel at value 100 and 130 will be considered equal if the threshold is set at 40 but different if set at 20.

2. Ring Size - the filter width used to analyze the surrounding pixels with regards to the center pixel.

3. Display Shape, Color, Size - configures the point indicator graphics.

4. Perform Non-Maxmimal Suppression - corner points are often identified in clumps of pixels. The non-maximal suppression will "suppress" or remove those pixels that are not the maximum value in a set filter ring size.

5. Corner Isolation - despite non-maximal suppression additional space between points is sometimes needed. The corner isolation number will ensure that a point is isolated within the specified number of pixels.

6. Create RING_CORNER Array - creates a VBScript accessible array of the point coordinates identified by the ring corner module.

Example

Source	Ring Corners Identified

Variables

RING_CORNER - x_coord, y_coord array list of identified points

For more information

Edward Rosten's FAST

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