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From: rjd@mda.ca (Robert Doerksen)
Message-Id: <9311221853.AA17392@ mda.ca>
To: tiff@sgi.sgi.com
Subject: RE: PhotoInterp field value for Complex imagery
Sender: tiff-owner@sgi.sgi.com

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.

Rob Doerksen



----- Begin Included Message -----

>From felix.lee@aldus.com Fri Nov 19 17:54:15 1993
To: rjd@mda.ca (Robert Doerksen)
From: felix.lee@aldus.com (Felix Lee,Eng)
Organization: Aldus Corporation, Seattle, WA 
Date: Fri, 19 Nov 1993 17:51:37 PDT
Subject: RE: Private value for PhotoInterp field
Content-Length: 3763

Rob,

The value I've assigned you for the PhotometricInterpretation field is:

   32837

Regards,

Felix Lee
Aldus Developer
Relations
_______________________________________________________________________________

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
> purposes).
> 
Thanks,
Rob Doerksen



> 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
> Carlsen
> ______________________________________________________________________________


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