INDEFD –> INDEFR in imio (fwd)

Doug Tody wrote on May 14, 1998

---------- Forwarded message ----------
Date: Thu, 14 May 1998 14:21:19 -0700 (MST)
Subject: Re: INDEFD --> INDEFR in imio

> When converting from double to single precision, imio does not convert
> INDEF values.  The following test routine illustrates the problem.
> I suspect this was introduced when the value of INDEFD was changed
> from 1.6d38 to 1.6d308.

Phil, by design, and for reasons of efficiency, IMIO does not permit pixel
values to be INDEF.  Pixel masks should be used to flag bad image pixels.  If
you store an INDEF-valued pixel in an image, IMIO will treat it like any
other pixel value; operations such as type conversion mail fail entirely.  In
general the INDEF value is machine dependent.  The recommended approach is to
replace bad pixels in an image with artifically generated values, and use a
bad pixel mask to flag such pixels and exclude them from most subsequent
analysis.

	- Doug

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Last post on May 14, 1998