docs: public static <T extends ImageGray<T>>
  	double block_zero( T integral , int x0 , int y0 , int x1 , int y1 )
  	{
  		if( integral instanceof GrayF32) {
  			return IntegralImageOps.block_zero((GrayF32)integral,x0,y0,x1,y1);
  		} else if( integral instanceof GrayF64) {
  			return IntegralImageOps.block_zero((GrayF64)integral,x0,y0,x1,y1);
  		} else if( integral instanceof GrayS32) {
  			return IntegralImageOps.block_zero((GrayS32)integral,x0,y0,x1,y1);
  		} else if( integral instanceof GrayS64) {
  			return IntegralImageOps.block_zero((GrayS64)integral,x0,y0,x1,y1);
  		} else {
  			throw new IllegalArgumentException("Unknown input type");
  		}
  	}