public function offsetGet($offset): Image
    {
        return $this->offsetExists($offset) ? $this->extract_band($offset) : null;
    }
public function offsetGet($offset): Image
    {
        return $this->offsetExists($offset) ? $this->extract_band($offset) : null;
    }
public function offsetGet ( $ offset ) : Image { return $ this -> offsetExists ( $ offset ) ? $ this -> extract_band ( $ offset ) : null ; }
Get band from image.

@param mixed $offset The index to fetch.

@throws Exception

@return Image the extracted band.
Get band from image .