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Re: 16 bit Tiff image [message #58925] Thu, 28 February 2008 00:09 Go to next message
Andrew Cool is currently offline  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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Re: 16 bit Tiff image [message #58926 is a reply to message #58925] Wed, 27 February 2008 23:01 Go to previous messageGo to next message
Stefano Scardigli is currently offline  Stefano Scardigli
Messages: 7
Registered: February 2008
Junior Member
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)

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Re: 16 bit Tiff image [message #58927 is a reply to message #58926] Wed, 27 February 2008 22:52 Go to previous messageGo to next message
Stefano Scardigli is currently offline  Stefano Scardigli
Messages: 7
Registered: February 2008
Junior Member
On Wed, 27 Feb 2008 16:45:54 -0700, Jean H wrote:

>>> IDL> img=read_tiff("V13A5.00.tif",/unsigned)
>
>>> 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
>
> Could it be a litle/big endian problem?
> after reading img, try to do:
> SWAP_ENDIAN_INPLACE, img
> and see if it helps (or if it brings you wayyyyy off)
> Jean

I haven't SWAP_ENDIAN_INPLACE in my IDL 5.1 !!!

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Re: 16 bit Tiff image [message #58931 is a reply to message #58927] Wed, 27 February 2008 15:45 Go to previous messageGo to next message
Jean H. is currently offline  Jean H.
Messages: 472
Registered: July 2006
Senior Member
>> IDL> img=read_tiff("V13A5.00.tif",/unsigned)

>> 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

Could it be a litle/big endian problem?
after reading img, try to do:
SWAP_ENDIAN_INPLACE, img
and see if it helps (or if it brings you wayyyyy off)
Jean

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Re: 16 bit Tiff image [message #58934 is a reply to message #58931] Wed, 27 February 2008 15:12 Go to previous messageGo to next message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
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

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming (www.dfanning.com)
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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Re: 16 bit Tiff image [message #58935 is a reply to message #58934] Wed, 27 February 2008 15:03 Go to previous messageGo to next message
Stefano Scardigli is currently offline  Stefano Scardigli
Messages: 7
Registered: February 2008
Junior Member
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)!

Stefano Scardigli



On Wed, 27 Feb 2008 14:01:12 -0700, Jean H wrote:

> Stefano Scardigli wrote:
>> nothing is changed
>>
>> 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",img,/SHORT
>> IDL> print,max(img)
>> 255
>> IDL> help,img
>> IMG BYTE = Array[1000, 1000]
>
> img is a long and you try to save it as an integer... have you tried
>
> write_tiff,"prova.tiff",fix(img),/SHORT
> or
> write_tiff,"prova.tiff",img,/LONG
> ?
>
> Jean

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Re: 16 bit Tiff image [message #58938 is a reply to message #58935] Wed, 27 February 2008 13:26 Go to previous messageGo to next message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
Stefano Scardigli writes:

> nothing is changed
>
> 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",img,/SHORT
> IDL> print,max(img)
> 255
> IDL> help,img
> IMG BYTE = Array[1000, 1000]

Well, I don't know what to tell you. That's not what
happens when I type the code. :-(

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming (www.dfanning.com)
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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Re: 16 bit Tiff image [message #58939 is a reply to message #58938] Wed, 27 February 2008 13:01 Go to previous messageGo to next message
Jean H. is currently offline  Jean H.
Messages: 472
Registered: July 2006
Senior Member
Stefano Scardigli wrote:
> nothing is changed
>
> 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",img,/SHORT
> IDL> print,max(img)
> 255
> IDL> help,img
> IMG BYTE = Array[1000, 1000]

img is a long and you try to save it as an integer... have you tried

write_tiff,"prova.tiff",fix(img),/SHORT
or
write_tiff,"prova.tiff",img,/LONG
?

Jean

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Re: 16 bit Tiff image [message #58942 is a reply to message #58939] Wed, 27 February 2008 12:32 Go to previous messageGo to next message
Stefano Scardigli is currently offline  Stefano Scardigli
Messages: 7
Registered: February 2008
Junior Member
nothing is changed

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",img,/SHORT
IDL> print,max(img)
255
IDL> help,img
IMG BYTE = Array[1000, 1000]

On Wed, 27 Feb 2008 12:12:16 -0700, David Fanning wrote:

> Stefano Scardigli writes:
>
>> I'm new in using IDL and I'm using an old version too.
>> I have a strange problem in writing 16 bit TIFF files
>>
>> this is the dump of my problem (I omitted the unuseful rows):
>>
>> IDL Version 5.1 (OSF alpha). Research Systems, Inc.
>> 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",img
>> IDL> print,max(img)
>> 255
>> IDL> img2=read_tiff("prova.tiff",/unsigned)
>> IDL> print,max(img2)
>> 255
>> IDL> help,img
>> IMG BYTE = Array[1000, 1000]
>> IDL> help,img2
>> IMG2 BYTE = Array[1000, 1000]
>> IDL>
>>
>> as you can see the file prova.tiff is a 8 bit image and also the array img
>> is changed from LONG to BYTE. I tried all the parameter of the write_tiff
>> procedure, but nothing change
>
> I think you forgot the SHORT keyword here:
>
> IDL> write_tiff,"prova.tiff",img
>
> This should be:
>
> IDL> write_tiff,"prova.tiff",img, /SHORT
>
> Cheers,
>
> David

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Re: 16 bit Tiff image [message #58944 is a reply to message #58942] Wed, 27 February 2008 11:12 Go to previous messageGo to next message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
Stefano Scardigli writes:

> I'm new in using IDL and I'm using an old version too.
> I have a strange problem in writing 16 bit TIFF files
>
> this is the dump of my problem (I omitted the unuseful rows):
>
> IDL Version 5.1 (OSF alpha). Research Systems, Inc.
> 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",img
> IDL> print,max(img)
> 255
> IDL> img2=read_tiff("prova.tiff",/unsigned)
> IDL> print,max(img2)
> 255
> IDL> help,img
> IMG BYTE = Array[1000, 1000]
> IDL> help,img2
> IMG2 BYTE = Array[1000, 1000]
> IDL>
>
> as you can see the file prova.tiff is a 8 bit image and also the array img
> is changed from LONG to BYTE. I tried all the parameter of the write_tiff
> procedure, but nothing change

I think you forgot the SHORT keyword here:

IDL> write_tiff,"prova.tiff",img

This should be:

IDL> write_tiff,"prova.tiff",img, /SHORT

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming (www.dfanning.com)
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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Re: 16 bit Tiff image [message #58995 is a reply to message #58934] Thu, 28 February 2008 23:34 Go to previous message
Stefano Scardigli is currently offline  Stefano Scardigli
Messages: 7
Registered: February 2008
Junior Member
what a mess =:-O

I'm on IDL 5.1 and I'm working on a remote server via ssh.

I haven't QUERY_TIFF
I haven't SWAP_ENDIAN_INPLACE

the images I'm dealing with are about 24 Mb each and they seem fine.
I'm thinking about some problem with multiband image (what is thinking
IDL) and the monocromatic mine.


I'm thinking to give up to this IDL.
I spent a lot of time in compiling GDL and all the other stuff it
requires. But I'm still not sure it is working fine.

Any idea?

Thanks to all


Stefano Scardigli


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

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