Hi,

I'd like to read 64-bit TIF Image with imread function. Is there any easy way? I know that it should be possible in my version (7.10.0 R2010a).

Thanks a lot
Marek
__
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"Marek " <nahradniucet@gmail.com> wrote in message 
news:i6q2jj$8jv$1@fred.mathworks.com...
> Hi,
>
> I'd like to read 64-bit TIF Image with imread function. Is there any easy 
> way? I know that it should be possible in my version (7.10.0 R2010a).

Did you try just calling IMREAD on the image file?  If so, what happened? 
Did it throw a warning?  Did it error?  Did it return the wrong data?

-- 
Steve Lord
slord@mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
To contact Technical Support use the Contact Us link on 
http://www.mathworks.com 

On 9/15/2010 9:45 AM, Steven_Lord wrote:
>
>
> "Marek " <nahradniucet@gmail.com> wrote in message
> news:i6q2jj$8jv$1@fred.mathworks.com...
>> Hi,
>>
>> I'd like to read 64-bit TIF Image with imread function. Is there any
>> easy way? I know that it should be possible in my version (7.10.0
>> R2010a).
>
> Did you try just calling IMREAD on the image file? If so, what happened?
> Did it throw a warning? Did it error? Did it return the wrong data?
>

Where did you get a "64-bit" TIFF file?  There is no indication in the 
TIFF spec (http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf) 
that this is allowed. If you search the entire spec for information 
about the BitsPerSample tag, you'll find that it is restricted to 1, 4, 
or 8 for baseline TIFF images. In the extensions section the additional 
values of 16 and 32 are mentioned.

There's nothing about 64 being valid for BitsPerSample.

---
Steve Eddins
http://blogs.mathworks.com/steve/

Calling imread doesn't throw warning nor error, but maximum of resulting matrix is 32767. The image is output of VSpec, program for handling camera and spectrograph.

Yeh, you are right that 64-bit TIF doesn't correspond specification. Program VSpec was probably from some reason forced to save image in double precision, which may cause the problem.

Thank you for your advices and comments.
Marek

On 9/15/2010 4:05 PM, Marek wrote:
> Calling imread doesn't throw warning nor error, but maximum of resulting
> matrix is 32767. The image is output of VSpec, program for handling
> camera and spectrograph.
>
> Yeh, you are right that 64-bit TIF doesn't correspond specification.
> Program VSpec was probably from some reason forced to save image in
> double precision, which may cause the problem.
>
> Thank you for your advices and comments.
> Marek

How do you know the file is "64-bit"? What is the output of imfinfo for 
the file?

---
Steve Eddins
http://blogs.mathworks.com/steve/

Hi Marek, 

Even though it's a bit odd, IMREAD should be able to handle 64-bit floating point MinIsBlack images.  Since you have 2010a, the Tiff object is also available, can read such images, and the results should agree, i.e.

    d1 = imread(file);
    t = Tiff(file);
    d2 = t.read();   % d1 and d2 should be identical for this kind of image


"Marek " <nahradniucet@gmail.com> wrote in message <i6r8tf$14b$1@fred.mathworks.com>...
> Calling imread doesn't throw warning nor error, but maximum of resulting matrix is 32767. The image is output of VSpec, program for handling camera and spectrograph.
> 
> Yeh, you are right that 64-bit TIF doesn't correspond specification. Program VSpec was probably from some reason forced to save image in double precision, which may cause the problem.
> 
> Thank you for your advices and comments.
> Marek