Linear Intensity Changes (p <-- a + bp)

This option provides a simple method of adjusting the intensity range of an image contained within a buffer. By specifying the (real) constants a and b, the new intensity may be linearly adjusted using the relation

           p <-- a + bp

The transformation is performed using the onboard ALU.

Transform what buffer ?

This facility is able to opearate on a list of buffers. Any buffer may be processed. Extended memory buffers are first copied to buffer 0 before processing, and copied back after.

Another buffer ? Specifying yes (<Y>) allows another buffer to be added to the list of those being processed, while no (<N>) allows DigImage to continue with the procesing.

Transformation of the form p <-- a + bp Constant term: a ?

Real value specifying the offset of the transformation.

Scale term: b ?

Real value specifying the scale of the transformation.

Saturate or Wrap ?

The answer to this question determines how results falling outside the eight bit range be treated. If <W> is specified, then the result modulo 256 will be used. If <S> is specified, then results exceeding 255 will be set to 255, and those below zero will be set to zero.

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Stuart Dalziel, last page update: 19 February 1996