Gradient Phase
ThexFphase
function computes the polar angles of two images. The input images are x-gradient and y-gradient images of type 16S. The output image is of same type as the input image.
For radians:
For degrees:
API Syntax
template void xFphase(xF::Mat & _src_matx,xF::Mat & _src_maty,xF::Mat & _dst_mat)
Parameter Descriptions
The following table describes the template and the function parameters.
Parameter | Description |
---|---|
RET_TYPE | Output format can be either in radians or degrees. Options are XF_RADIANS or XF_DEGREES.
|
SRC_T | Input pixel type. Only 16-bit, signed, 1 channel is supported (XF_16SC1) |
DST_T | Output pixel type. Only 16-bit, signed, 1 channel is supported (XF_16SC1) |
ROWS | Maximum height of input and output image (must be a multiple of 8) |
COLS | Maximum width of input and output image (must be a multiple of 8) |
NPC | Number of pixels to be processed per cycle; possible options are XF_NPPC1 and XF_NPPC8 for 1 pixel and 8 pixel operations respectively. |
_src_matx | First input, x-gradient image. |
_src_maty | Second input, y-gradient image. |
_dst_mat | Output, phase computed image. |
|
Resource Utilization
The following table summarizes the resource utilization of the kernel in different configurations, generated usingVivado HLS 2017.1tool for theXilinx Xczu9eg-ffvb1156-1-i-es11 FPGA, to process a grayscale HD (1080x1920) image.
Name | Resource Utilization | |
---|---|---|
1 pixel | 8 pixel | |
300 MHz | 150 MHz | |
BRAM_18K | 6 | 24 |
DSP48E | 6 | 19 |
FF | 873 | 2396 |
LUT | 753 | 3895 |
CLB | 185 | 832 |
Performance Estimate
The following table summarizes the performance of the kernel in different configurations, as generated usingVivado HLS 2017.1tool for theXilinx Xczu9eg-ffvb1156-1-i-es1, to process a grayscale HD (1080x1920) image.
Operating Mode | Operating Frequency (MHz) |
Latency Estimate (ms) |
---|---|---|
1 pixel | 300 | 7.2 |
8 pixel | 150 | 1.7 |
Deviation fromOpenCV
In xFphase implementation, the output is returned in a fixed point format. If XF_RADIANS option is selected, xFphase API will return result in Q4.12 format. The output range is (0, 2 pi). If XF_DEGREES option is selected, xFphase API will return result in Q10.6 degrees and output range is (0, 360);