public Matrix int setIntegralImage if grayImage null Matrix int Integr

public Matrix<int> setIntegralImage() {
 if (grayImage != null) {
  Matrix<int> IntegralImage = new Matrix<int>(grayImage.Size);
  Matrix<int> IntegralImageSquare = new Matrix<int>(grayImage.Size);
  for (int i = 0; i < IntegralImage.Height; i++) {
   for (int j = 0; j < IntegralImage.Width; j++) {
    IntegralImage.Data[i, j] = grayImage.Data[i, j, 0];
    IntegralImageSquare.Data[i, j] = grayImage.Data[i, j, 0] * grayImage.Data[i, j, 0];

    if (i > 0 && j > 0) {
     IntegralImage.Data[i, j] += IntegralImage.Data[i - 1, j - 1];
     IntegralImageSquare.Data[i, j] += IntegralImageSquare.Data[i - 1, j - 1];
    } 
    if (i > 0) {
     IntegralImage.Data[i, j] += -IntegralImage.Data[i - 1, j];
     IntegralImageSquare.Data[i, j] += -IntegralImageSquare.Data[i - 1, j];
    }
    if (j > 0) {
     IntegralImage.Data[i, j] += -IntegralImage.Data[i, j - 1];
     IntegralImageSquare.Data[i, j] += IntegralImageSquare.Data[i, j - 1];
    }
   }
  }
  // set values
  this.IntegralImage = IntegralImage;
  this.IntegralImageSquare = IntegralImageSquare;

  // return result
  return IntegralImage;
 }
 // set null values
 this.IntegralImage = null;
 this.IntegralImageSquare = null;
 // return null
 return null;
}