If subtracting background for tracing, we convert arrays of unsigned 2-byte integers to signed 2-byte integers, to handle properly the possibility that a pixel value in background exceeds a pixel value in non-background. This, however, will be problematic for very high pixel values, near the upper bound of the domain for the unsigned 2-byte integer type. We should instead convert to signed 4-byte integers (numpy.int32).
If subtracting background for tracing, we convert arrays of unsigned 2-byte integers to signed 2-byte integers, to handle properly the possibility that a pixel value in background exceeds a pixel value in non-background. This, however, will be problematic for very high pixel values, near the upper bound of the domain for the unsigned 2-byte integer type. We should instead convert to signed 4-byte integers (
numpy.int32).