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AIR Linear Transformation

(3 posts)
  • Started 6 years ago by chasiubao73
  • Latest reply from chasiubao73
  1. chasiubao73


    We have a question about the AIR Linear co-registration step that we perform. We are doing an atlas (Eve)to subject AIR Linear transformation. What happens is that we have noticed that the resultant brain image is almost identical to the original Eve atlas brain.

    We have done the necessary pre-processing steps to ensure that the background noise and skull stripping are as matched closely to one another as much as possible.

    Any suggestions as to why our atlas to subject registration yields a resultant image almost identical to the original starting Eve brain?

    Thank you for all your assistance in our research endeavors.

    Posted 6 years ago #
  2. koishi

    Dear chasiubao73,

    If you chose 6-parameter rigid, the result is identical to the Eve, in terms of the size and shape. Rigid transformation just change the position and angle of the image.
    If you chose 9- or 12- parameter affine, and still the result is identical to the Eve, please try the followings.
    1) Before you apply AIR, match the image centers of the template (your image) and the subject (Eve). The center of Eve is located in the upper edge of the body of the fornix. The "shift" function of the Diffeomap is useful to match the centers.
    2) Please make sure that the image contrast of your image and that of the Eve are close enough. You can modify the image contrast before you apply AIR.
    Hope this helps.

    Best regards,

    Kenichi Oishi

    Posted 6 years ago #
  3. chasiubao73

    Hi Kenichi,

    Thank you for your response. Yes, we use affine 12. We will try adjusting the contrast of our subject and template images before applying AIR Linear in Diffeomap.

    Posted 6 years ago #

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