[Insight-users] A problem of Sampling in the Mattes Mutual Information Registration

[Luis Ibanez]

Hi Caojie,

The size (in pixels) of the PET images shouldn't
be a problem, as long as its pixel spacing is set
correctly.

What will probably be a challenge is the lack of
recognizable anatomical structures in the PET image.


   Regards,


     Luis


-----------
曹杰 wrote:
> Hi Luis,
>        Thank you for your help! But I doubt whether CT and PET could registrate since the PET images are too small and dark.
>                                                         Cao Jie
> 
> 
>>Hi Caojie,
>>
>>The recommended number of sampling points is 3% of the total
>>number of pixels in the region that you want to register.
>>
>>If you use the mask, then the number of samples should be close
>>to 3% of the number of pixels inside the mask.
>>
>>
>>Note that this is just a recommended value. Take it as a good
>>starting parameter, but be aware that you may have to tune its
>>value.
>>
>>In practice, it is more critical to select a good value for the
>>number of histogram bins than for the number of samples.
>>
>>
>>
>>Regards,
>>
>>
>>   Luis
>>
>>
>>
>>----------------
>>曹杰 wrote:
>>
>>
>>>Hi,
>>>    This is my problem:
>>>    When I use the Mattes Mutual Information Metric to registrate,
>>>
>>>    the fixedimage's size is 128*128*20----(PET),spacing is  (3.92,3.92,4.25) 
>>>    the movingimage's size is 512*512*20----(CT),spacing is  (0.98,0.98,4.25)
>>>    
>>>    How many sample points should I take to registrate?
>>>Since the fixedimage is PET images, and in each image the content of the image is a small part,most of the image is the background pixels whose intensities are 0 .   According to this situation,how many sample points should be the best
>>>and need I use the FixedImageMask? If using the mask,how many sample points should be taken?
>>>    Thank you!
>>>                                                      ITK user   Cao Jie
>>>
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>>
>>
>>
>>
>>
> 
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