[ITK-users] Convert image, part 2

[Tammy Diprima]

I've just been told that I'm not allowed to convert the 32U to 16U because
of risk of distortion.

I figured it *should* be ok, since it's one channel.

So what I've been tasked to do, is iterate through the pixels and copy each
to a new cv::Mat_<int> image.  And I'm doing this conversion in order to
pass this ITK image as a parameter to someone else's program that takes an
opencv image as a parameter.

Right now I'm an image-processing noobie, so I'd like your option.  *Do* I
have to worry about distortion in this case?  How can I prove it?  It's
grayscale.  *Is* the pixel iteration a good idea?  I don't know why we're
using 32U for grayscale in the first place; there's no way we're going to
have more than 255 objects...

Thanks,
Tammy


On 5 September 2016 at 18:46, Tammy wrote:

Hi Dženan,
>
>
> Yes, that makes sense.  Thanks very much for your help.
>
>
> - Tammy
>
>
> On 5 September 2016 at 15:07, Dženan Zukić wrote:
>
>> Hi Tammy,
>>
>> the docs
>> <http://docs.opencv.org/2.4/modules/core/doc/basic_structures.html> list
>> unsigned short and int, but not unsigned int. I don't know whether this int
>> is equal to short or long. But from \ITK-git\Modules\Video\BridgeO
>> penCV\include\itkOpenCVImageBridge.hxx, line 50 these are supported
>> cases:
>> IPL_DEPTH_8U
>> IPL_DEPTH_8S
>> IPL_DEPTH_16U
>> IPL_DEPTH_16S
>> IPL_DEPTH_32F
>> IPL_DEPTH_64F
>>
>> To convert to 16U (which is closest to your 32U), you should use cast
>> filter <https://itk.org/Doxygen/html/classitk_1_1CastImageFilter.html> (that's
>> your option A).
>>
>> Regards,
>> Dženan
>>
>> On Mon, Sep 5, 2016 at 1:31 PM, Tammy wrote:
>>
>>> Greetings!  Hope everyone is having a good day...
>>>
>>> So... we are passing around a grayscale image... and we're using
>>> unsigned int (as opposed to unsigned char):
>>> typedef itk::Image<unsigned int, ImageDimension> itkUIntImageType;
>>> typedef itkUIntImageType itkLabelImageType;
>>>
>>> I need to convert it to cv::Mat in order to pass it to another program:
>>> cv::Mat resultImage = itk::OpenCVImageBridge::ITKImageToCVMat<
>>> itkLabelImageType >( m_objectLabelImage );
>>>
>>> The problem is, the compiler is telling me "OpenCV does not support the
>>> input pixel type".
>>>
>>> So my question is -- is this true?  Can I only convert from unsigned
>>> char?
>>> Would a good solution be to:
>>> A) Convert from one pixel type to another, or
>>> B) Or can I just read in the m_objectLabelImage to an Image::Pointer
>>> thing that is of type unsigned char?
>>>
>>> Thanks!
>>>
>>>
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