OpenCv ,Hls ,Video Processing :How to use hls::Range() to set ROI(Region of Interest)?Help!!!

Question

Hi,
    I have one problem,I want to use hls::Range() to set ROI(Region of Interest),and  I could not how to use  it corretly.Anyone can help me ? And give me one example. 
1.  Functions are defined as follows:
hls::Range
Synopsis
template<int ROWS, int COLS, int SRC_T, int DST_T, typename P_T>
void hls::Range (
hls::Mat<ROWS, COLS, SRC_T>& src,
hls::Mat<ROWS, COLS, DST_T>& dst,
P_T start,
P_T end);
Parameter                                                  Description
src                                                              Input single-channel image
dst                                                              Output single-channel image
start                                                            Left boundary value of the range
end                                                             Right boundary value of the range
Description
• Sets all value in image src by the following rule and return the result as image dst.
• Image data must be stored in src.
• The image data of dst must be empty before invoking.
• Invoking this function consumes the data in src and fills the image data of dst.
• src and dst must have the same size and be single-channel images.
OpenCV Reference
• cvRange
2.I use it  as follow，but it can not work corretly.
#define MAX_WIDTH 640
#define MAX_HEIGHT 480
typedef hls::stream<ap_axiu<32,1,1,1> > AXI_STREAM;
typedef hls::Scalar<3, unsigned char> RGB_PIXEL;
typedef hls::Mat<MAX_HEIGHT, MAX_WIDTH, HLS_8UC3> RGB_IMAGE;
#if 1
void image_filter(AXI_STREAM& INPUT_STREAM, AXI_STREAM& OUTPUT_STREAM, int rows, int cols) {
//Create AXI streaming interfaces for the core
#pragma HLS INTERFACE axis port=INPUT_STREAM
#pragma HLS INTERFACE axis port=OUTPUT_STREAM
#pragma HLS RESOURCE core=AXI_SLAVE variable=rows metadata="-bus_bundle CONTROL_BUS"
#pragma HLS RESOURCE core=AXI_SLAVE variable=cols metadata="-bus_bundle CONTROL_BUS"
#pragma HLS RESOURCE core=AXI_SLAVE variable=return metadata="-bus_bundle CONTROL_BUS"
#pragma HLS INTERFACE ap_stable port=rows
#pragma HLS INTERFACE ap_stable port=cols
RGB_IMAGE img_0(rows, cols);   
hls::Mat<MAX_HEIGHT,MAX_WIDTH,HLS_8UC1> gray(rows,cols);
hls::Mat<MAX_HEIGHT,MAX_WIDTH,HLS_8UC1> range_1(rows,cols);
#pragma HLS dataflow
 hls::AXIvideo2Mat(INPUT_STREAM, img_0);
 hls::CvtColor<HLS_RGB2GRAY>(img_0,gray);;
hls::Range(gray,range_1,50,600);       //     I use hls::Range() like it , is it  right?Help！！！
hls::CvtColor<HLS_GRAY2RGB>(range_1,img_1);
hls::Mat2AXIvideo(img_1, OUTPUT_STREAM);
#endif

Answer 1

Anyone could help me?