BUG: fake zero padding

Modules/Filtering/Convolution/include/otbOverlapSaveConvolutionImageFilter.txx

@@ -186,6 +186,9 @@ OverlapSaveConvolutionImageFilter<TInputImage, TOutputImage, TBoundaryCondition>
   unsigned int leftskip = static_cast<unsigned int>(std::max(0L, inputIndex[0] - pieceIndex[0]));
   unsigned int topskip =  pieceSize[0] * static_cast<unsigned int>(std::max(0L, inputIndex[1] - pieceIndex[1]));
 
+  // zero filling
+  memset(inputPiece,0,pieceNbOfPixel * sizeof(InputPixelType));
+
   // Filling the buffer with image values
   for (l = 0; l < inputSize[1]; ++l)
     {
@@ -205,6 +208,9 @@ OverlapSaveConvolutionImageFilter<TInputImage, TOutputImage, TBoundaryCondition>
                                                                       filterPieceFFT,
                                                                       FFTW_MEASURE);
 
+  // zero filling
+  memset(resampledFilterPiece,0,pieceNbOfPixel * sizeof(InputPixelType));
+
   k = 0;
   // Filling the buffer with filter values
   for (j = 0; j < sizeOfFilter[1]; ++j)