code: public int[] getUnsignedPixelValues(WritableRaster raster) {
  		short[] pixelValues = getPixelValues(raster);
  		int[] unsignedPixelValues = getUnsignedPixelValues(pixelValues);
  		return unsignedPixelValues;
  	}
docs: Get the pixel values of the raster as 16 bit unsigned integer values
  
  @param raster
  image raster
  @return unsigned integer pixel values