IPPM WarpAffine Center

[CRoec1]

Hi experts,

i want to perform an affine warp of my image. Is there a function which supports warping in respect to the center of the image (and not to the top-left origin of the ROI)? I tried the ippiWarpAffineLinear_32f_C1R for my case but without success.

Any idea? An example would be great :)!

[Jonghak_K_Intel]

Hi Christian,

  I'm not sure if IPP provides such a function that supports warping in respect to the center of the image, since it would have to distort axes and things can become confusing.

  Did you happen to find the reference manual of affine warping part? here's the link : https://software.intel.com/en-us/node/529049 You can find examples on that page also. 

 You can always find your offline reference at "C:\Program Files (x86)\Intel\System Studio 2015 for Windows.x.xxx\documentation\en_US\ipp\ipp_manual\index.htm" as default.  Search for " Warp Affine Functions " then you will easily find the same information.

 Thank you :)

[Valentin_K_Intel]

Hi Christian,

As far as I understood the problem to perform warping in respect to the center of the source image we need to shift the point (0,0) to the source image center point (x_c, y_c) = (half width of the source image, half height of the source image) . So we need to recompute the affine transform coefficients by the following way:

c₀₂ = c₀₂ - c₀₀ * x_c - c₀₁ * y_c
c₁₂ = c₁₂ - c₁₀ * x_c - c₁₁ * y_c

After that the function ippiWarpAffineLinear_32f_C1R can be used for affine warping.

Best regards,
Valentin