Using InstanceWeights in vl_nnloss

[HadarGorodissky]

I'm trying to use weighted loss for the FCN training on only 1 category (+BG).
I want to use the InstanceWeights but it seems like for very different weighting the result is the same. I was wondering if someone used this parameter for training and it helped him
The size of the InstanceWeights Im passing is : HxWx1xN with value between 0-1 where each label (object, BG) get the same value i.e.
for j=1:length(classWeights)
instanceWeights (labels==j)=classWeights(j);
end

I will be thankful to know how you decided on the value of instanceWeights and what are the value range you used …

Thanks