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Re: 16 bit Tiff image [message #58925]

Thu, 28 February 2008 00:09

Andrew Cool
Messages: 219
Registered: January 1996

Senior Member

On Feb 28, 5:01 pm, Stefano Scardigli <s.scardi...@libero.it> wrote:
> On Wed, 27 Feb 2008 16:12:24 -0700, David Fanning wrote:
>> Stefano Scardigli writes:
>
>>> better, thanks:
>
>>> IDL> img=read_tiff("V13A5.00.tif",/unsigned)
>>> IDL> help,img
>>> IMG LONG = Array[1000, 1000]
>>> IDL> print,max(img)
>>> 65535
>>> IDL> write_tiff,"prova.tiff",fix(img),/SHORT <---------
>>> IDL> help,img
>>> IMG LONG = Array[1000, 1000]
>>> IDL> print,max(img)
>>> 65535
>>> IDL> img2=read_tiff("prova.tiff",/unsigned)
>>> IDL> help,img2
>>> IMG2 LONG = Array[1000, 1000]
>>> IDL> print,max(img2)
>>> 255
>
>>> and now both img and img2 are LONG, but the reloaded img2 is still shrunk
>>> to 255 levels (ie 8 bit)!
>
>> I still don't think so. Are you being *very*
>> careful with your variables? You might try using
>> a .reset after you write the file and before you
>> read it again. I think it is not possible to get
>> what you are getting. :-)
>
>> Cheers,
>
>> David
>
> I'm very careful with my variables, and all the "code" I'm using is just
> this:
>
> img=read_tiff("V13A5.00.tif",/unsigned)
> help,img
> print,max(img)
> write_tiff,"prova.tiff",fix(img),/LONG
> help,img
> print,max(img)
> img2=read_tiff("prova.tiff",/unsigned)
> help,img2
> print,max(img2)

My IDL5.3 manuals say that /UNSIGNED is used to read in unsigned 16-
bit integer data and convert it to
unsigned 32-bit longword arrays. That keyword was obsolete by IDL 5.3.

Are you quite sure of the format of the data in your TIFF file? Have
your tried QUERY_TIFF and inspected the resultant information
structure?

Perhaps you could post the TIFF file somewhere for us to investigate?

Cheers,

Andrew

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[Message index]

		Re: 16 bit Tiff image By: Andrew Cool on Thu, 28 February 2008 00:09
		Re: 16 bit Tiff image By: Stefano Scardigli on Wed, 27 February 2008 23:01
		Re: 16 bit Tiff image By: Stefano Scardigli on Wed, 27 February 2008 22:52
		Re: 16 bit Tiff image By: Jean H. on Wed, 27 February 2008 15:45
		Re: 16 bit Tiff image By: David Fanning on Wed, 27 February 2008 15:12
		Re: 16 bit Tiff image By: Stefano Scardigli on Wed, 27 February 2008 15:03
		Re: 16 bit Tiff image By: David Fanning on Wed, 27 February 2008 13:26
		Re: 16 bit Tiff image By: Jean H. on Wed, 27 February 2008 13:01
		Re: 16 bit Tiff image By: Stefano Scardigli on Wed, 27 February 2008 12:32
		Re: 16 bit Tiff image By: David Fanning on Wed, 27 February 2008 11:12
		Re: 16 bit Tiff image By: Stefano Scardigli on Thu, 28 February 2008 23:34

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