[Insight-users] 16-bit -> 8-bit pixels

[Gib Bogle]

Thanks Bill,

It turns out that what I knew was not the case.  I was fooled by the way 
Irfanview reports image info.  In fact the files I've examined so far have a max 
value of 4096, i.e. they are using 12 bits, stored in 16 bits.  There's probably 
a much easier way, but I've written code to read each file and write the 
converted values into an 8-bit 3D image.

Cheers
Gib

On 14/09/2011 3:37 p.m., Bill Lorensen wrote:
> When you declare your image series reader use unsigned char as the type. The 
> reader will produce the output type regardless of the actual type in the files 
> themselves. It does so with a simple cast. This can be dangerous, but in your 
> case, you know the values are less than 255.
>
> On Tue, Sep 13, 2011 at 11:29 PM, Gib Bogle <g.bogle at auckland.ac.nz 
> <mailto:g.bogle at auckland.ac.nz>> wrote:
>
>     I'm reading a set of 2D tiff images and writing a 3D tiff (essentially the
>     example IO/ImageSeriesReadWrite.cxx).  The 2D tiffs have 16-bit pixels,
>     but the pixel values are all less than 255.  I want the output file to be
>     8-bit.  How should I do the conversion (the example ImageReadCastWrite
>     uses RescaleIntensityImageFilter to convert between different pixel
>     formats, but I do not want to rescale the values).
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