Measure gap widths
Measures gap widths using a gray-level profile.
- 1-by-N gray-scale profile vector originating typically from gray level profiling.
- The location of the first profile point in world coordinates.
- The location of the last profile point in world coordinates.
- Gap edge detection algorithm. Gap edges are detected from filtered profile using the selected algorithm.
- Smoothness of the profile filter. Small smoothness value works best with sharp edges. Large smoothness value gives better results if the edges are dull or the image is noisy.
- The following condition must be met at be met before a filtered profile entry is considered to be a start / end of a gap: Absolute mode: Filtered gray level must be larger than this. Differential mode: Rate of change must be larger than this. Gaussian zero crossing mode: Two consecutive 2nd order differences must be of opposite signs and their difference must be larger than
- Hysteresis to the threshold Absolute mode: The threshold must be exceeded by this number before the pixel is considered an edge. Differential mode: Pixel at which the rate of change is local maximum minus hysteresis is set as an edge. Gaussian zero crossing mode: N/A
- maximum number of gaps to be detected
- Filtered vector which is matched against the threshold. In absolute mode contains smoothed input profile. In differential mode contains filtered differences. In zero crossing mode contains filtered 2nd order differences.
- distance of the left edge of the gap from the beginning of the profile line in world coodinates.
- distance of the right edge of the gap from the beginning of the profile line in world coodinates.
- Width of the gap in world coordinates
- Type of the gap. 0 = dark gap, 1 = light gap.
- Magnitude of the filtered profile which exceeded the threshold for the left edge of this gap. The bigger the value, the sharper the edge is. Absolute mode: Maximum gray level in light gap and minimum gray level in dark gap. Differential mode: Maximum change in light gap (>0) and minimum change in dark gap (<0) at the left edge of the gap. Gaussian zero crossing mode: Difference between the two consecutive 2nd order differences with opposite signs.
- World coordinates of the left end of the gap on XY-plane
- World coordinates of the center of the gap on XY-plane
- World coordinates of the right end of the gap on XY-plane