regionprops Very slow on centroid identification

[Johannes Schoenberger]

Hi Jeff,

I mentioned this before, but since you do not care about individual regions, there is no reason to burden yourself with the overhead of the regionprops function.

Try this modified function:


```
def barycenter_skimage2(image,minx,miny,maxx,maxy,thresh,border,White_Mark):
  """
  skimage computation of the barycenter (moment 1 of image) on ZOI using regionprops
  """
  bw=image[minx:maxx+1,miny:maxy+1]>thresh
  if(White_Mark==False):
    bw=1-bw
  Onex,Oney=np.where(bw==1)
  minx_=Onex.min()
  maxx_=Onex.max()
  miny_=Oney.min()
  maxy_=Oney.max()
  M = measure.moments(bw.astype(np.double), order=1)
  Px=M[0, 1]/M[0, 0]
  Py=M[1, 0]/M[0, 0]
  Px+=minx
  Py+=miny
  # Determination of the new bounding box using global coordinates and the margin
  minx=minx-border+minx_
  miny=miny-border+miny_
  maxx=minx+border+maxx_
  maxy=miny+border+maxy_
  return Px,Py,minx,miny,maxx,maxy
```


We could add a templated version of the moments functions for uint8 to make this a fairer comparison. The regionprops function would also gain from this, since the `double` version is only used for the weighted moments.

Best, Johannes

> On Nov 26, 2014, at 9:28 AM, jeff witz <witzjean at gmail.com> wrote:
> 
> Hi,
> 
> Thank you all for your answers. finally I use OpenCV to perform the real-time computation and still use skimage for the initialisation on my real code. 
> 
> I've joined a file that allows one to compare the computation we need to make. 
> 
> There is a basic numpy method, the OpenCV one and the Skimage regionprops one. I don't find relevant to include a naive python implementation.
> 
> Please note that the values computed for visualization are for illustration only and doesn't represent a real experiment.
> 
> I Hope it can help to benchmark the future improvement of regionprops.
> 
> Best regards  
> 
> -- 
> You received this message because you are subscribed to the Google Groups "scikit-image" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to scikit-image+unsubscribe at googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
> <UnitTestExtenso.py>