Accumulate Squared
ThexFaccumulateSquarefunction adds the square of an image (src1) to the accumulator image (src2) and generates the accumulated result (dst).
The accumulated result is a separate argument in the function, instead of having src2 as the accumulated result. In this implementation, having a bi-directional accumulator is not possible as the function makes use of streams.
API Syntax
template void xFaccumulateSquare ( xF::Mat src1, xF::Mat src2, xF::Mat dst) Parameter Descriptions
The following table describes the template and the function parameters.
| Parameter | Description |
|---|---|
| SRC_T | Input pixel type. Only 8-bit, unsigned, 1 channel is supported (XF_8UC1) |
| DST_T | Output pixel type. Only 16-bit, unsigned, 1 channel is supported (XF_16UC1) |
| 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. |
| src1 | Input image |
| src2 | Input image |
| dst | Output image |
Resource Utilization
The following table summarizes the resource utilization in different configurations, generated usingVivado HLS 2017.1tool for theXilinx Xczu9eg-ffvb1156-1-i-es1FPGA, to process a grayscale HD (1080x1920) image.
| Operating Mode | Operating Frequency (MHz) |
Utilization Estimate | ||||
|---|---|---|---|---|---|---|
| BRAM_18K | DSP_48E | FF | LUT | CLB | ||
| 1 pixel | 300 | 0 | 1 | 71 | 52 | 14 |
| 8 pixel | 150 | 0 | 8 | 401 | 247 | 48 |
Performance Estimate
The following table summarizes the performance 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 | Latency Estimate |
|---|---|
| Max Latency (ms) | |
| 1 pixel operation (300 MHz) | 6.9 |
| 8 pixel operation (150 MHz) | 1.6 |
Deviation fromOpenCV
InOpenCVthe accumulated squared image is stored in the second input image. The src2 image acts as input as well as output.
Whereas, in the xfOpenCVimplementation, the accumulated squared image is stored separately.
