AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2003.12.03 06:20 "[Tiff] Double Precision TIFF images", by Chris Cox
2003.12.03 18:40 "[Tiff] Double Precision TIFF images", by Frank Warmerdam
2003.12.04 21:11 "[Tiff] Double Precision TIFF images", by Antonio Scuri
2003.12.04 21:22 "[Tiff] Double Precision TIFF images", by Frank Warmerdam
2003.12.05 21:23 "[Tiff] Double Precision TIFF images", by Chris Cox
2003.12.05 04:18 "[Tiff] Double Precision TIFF images", by Chris Cox
2004.01.23 20:30 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Bob Friesenhahn
2004.01.23 17:16 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Joris
2004.01.23 17:38 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam
2004.01.23 19:15 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Bob Friesenhahn
2004.01.23 20:17 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Andy Cave
2004.01.23 17:57 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Joris
2004.01.23 18:55 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam
2004.01.23 19:15 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Joris
2004.01.23 19:19 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Bob Friesenhahn
2004.01.23 19:24 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam
2004.01.23 20:12 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Chris Cox
2004.01.23 20:52 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Chris Cox

2004.01.23 18:55 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam

Frank Warmerdam wrote:

>"sample" == "band" == "channel" == "component" ==?

Thanks Frank. Now I know I finally did understand it correctly. Am I also

correct in thinking that the only proper way ignorant software (as in doesn't know about how the image came about or what it is software that

intended to contain) can correctly interpret this 3-channel image as a

> grayscale image with 2 extra channels that have no specified

application/meaning? If ignorant software were to have to render this image,

the correct thing to do is to render the first channel as grayscale, and others as far as rendering is concerned, is that right? I discard the

realize this may also be trivial questions, but this thread is very

confusing.

Joris,

I am by no means an authority on the TIFF specification. My interpretation of the file in question is that a sensible application should render the first band in greyscale and ignore the 2nd and 3rd since they are extra samples with no meaning attached. Without the ExtraSamples tag, I think an application should assume the file contains 3 greyscale bands which might be drawn in any number of ways. One way would be to draw 1 band, and give the user the ability to flip through to see the 2nd and 3rd. Another would be to just treat them as RGB (as many multispetral imaging packages will do with the first 3 bands of multispectral data).

A viewing application that only showed the first band as greyscale with no options to inspect the others would be acceptable and reasonable, but that viewer would have little utility in the rather small work of multispectral image processing (IMHO).

Best regards,

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