1993.11.22 18:53 "RE: PhotoInterp field value for Complex imagery", by Robert Doerksen
A project being worked on by MDA has a requirement to store imagery in TIFF format. Some of the imagery consists of two components, REAL and IMAGINARY (complex imagery). Because of the high ingest throughput rate, it is impractical to convert the two components of each pixel into a magnitude value before storing the data to disk. We decided to request a value for the PhotometricInterpretation field which would indicate that the stored data is complex imagery. The ALDUS Corporation has responded by allocating the value 32837 for this purpose.
If anybody else has similar requirements, or is dealing with similar imagery stored in TIFF format, I welcome comments about how the data is being stored, accessed, manipulated, etc.
The following paragraphs include some of the communications between ourselves and ALDUS.
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>From firstname.lastname@example.org Fri Nov 19 17:54:15 1993
To: email@example.com (Robert Doerksen)
From: firstname.lastname@example.org (Felix Lee,Eng)
Organization: Aldus Corporation, Seattle, WA
Date: Fri, 19 Nov 1993 17:51:37 PDT
Subject: RE: Private value for PhotoInterp field
The value I've assigned you for the PhotometricInterpretation field is:
From: Robert Doerksen on Fri, Nov 19, 1993 4:05 PM
Subject: Private value for PhotoInterp field
To: Felix Lee,Eng
Would you please assign a value for the PhotometricInterpretation field which would indicate that the data is stored as complex (REAL, IMAGINARY) imagery. I know of several firms who would find this useful, including (of course) ours.
> I am interested in storing a complex image as:
> SamplesPerPixel = 2 (ie: REAL, IMAG)
> BitsPerSample = 16, 16
> SampleType = unsigned integer
> PhotometricInterpretation = "new unique value indicating complex
> cartesian data"
> For our application, we would like the TIFF reader to read the two components
> of each pixel, and then calculate and display the magnitude as an 8-bit
> gray-scale (the least-sig 8 bits would be truncated for display
> You should also probably use SampleFormat to tell whether the real and
> complex parts are integer vs floating point.
> Just so there is no misunderstanding: unless this sort of data is likely to
> have special utility in the graphic arts field, it is not likely that Aldus
> products will be enhanced to read such complex data. However, it is
> possible to write a field-installable image import filter for PageMaker
> that can handle complex data, if you really need to do this sort of thing.
> - Steve
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