Northern Eclipse Help Reference

Adaptive Threshold

This function takes the current monochrome image and generates a new image that highlights local differences.  When an image has uneven illumination, or is “on top” of another object with varying intensity that has added to the objects brightness, this function can compensate for the “bottom” object or uneven background by looking only at local differences.  This allows you to then threshold an image that would otherwise be un-thresholdable.

Region Size specifies the size of the region to be considered “local” to the pixel.   Each pixel is defined to be in the center of the local region.  It is adaptive since every pixel has its own unique region.  All regions are square.  Despite the name, the function does not actually threshold the image but it does prepare the image to be thresheld when normally it would not be possible. 

This function is designed to highlight objects that are uniform in size.  The size of the object highlighted is directly proportional to the Region Size.  As the object size deviates from the ideal object size, the object becomes more suppressed in the destination image.  In the example above, the nucleus of the neuron was suppressed but the white dots “on” the neuron were enhanced as well as the dots on the dendrites.

See Also

Threshold, Auto Threshold Bright, Auto Threshold Dark


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