ROIAlign

ROIAlign from Mask-RCNN

this is an implenment of ROIAlign from Mask-RCNN: https://arxiv.org/abs/1703.06870. Considering there is no ROIAlign in matconvnet(http://www.vlfeat.org/matconvnet), I just wrote this implenment so that we can use roialign layer in matlab.

the code is written in CUDA(.cu) and mex file which you can use it in matlab with GPU. use the command in matlab:

mexcuda roialign.cu

to compile the file.

and then you should add these codes to vl_simplenn.m in matconvnet

case 'roialign'
  res(i+1).x = roialign(res(i).x,rois,l.subdivisions,l.transform);

this is forward propagation

case 'roialign'
  res(i).dzdx = roialign(res(i).x,rois,res(i+1).dzdx,l.subdivisions,l.transform);

this is backward propagation