Matrox GatorEye Series Installation And Technical Reference page 32

32 Chapter 3: Matrox GatorEye User Guide
You can specify the minimum average intensity level required to record a position,
using the LocatePeakMinIntensity feature. If you set this intensity level too high,
the laser range operation might not detect any peak in a column; in this case, it
sets the peak position to the maximum possible value of the destination position
buffer (that is, an invalid position). If you set this intensity level too low, the laser
range operation might detect a peak where there is none.
You can also specify the width of the neighborhood, using the LocatePeakWidth
feature. If set too wide, the laser range operation might not detect a peak unless
the minimum required average intensity level is lowered; since the laser range
operation averages intensity levels over the specified search width, darker pixels
will be included and lower the average intensity level. This will also reduce the
accuracy of the position. If the width is too narrow, the position and intensity that
the laser range operation registers for the peak will be imprecise. Setting the width
to be very narrow also makes the search more susceptible to image noise.
Source Image
A vertical scan of column n
You can record the position with sub-pixel accuracy by specifying the number of
fractional bits for a fixed-point approximation of the position, using the
LocatePeakFixedPointPosition feature. However, every fractional bit that you use
exponentially decreases the maximum position value that you can record.
}
Neighborhood in Neighborhood in
column n with the column n with the
highest average highest average
peak intensity value peak intensity value