The minMaxLoc function finds the minimum and maximum values in an
image and location of those values.
API Syntax
template<int SRC_T,int ROWS,int COLS,int NPC, int XFCVDEPTH_IN = _XFCVDEPTH_DEFAULT>
void minMaxLoc(xf::cv::Mat<SRC_T, ROWS, COLS, NPC, XFCVDEPTH_IN> & _src,int32_t *max_value, int32_t *min_value,uint16_t *_minlocx, uint16_t *_minlocy, uint16_t *_maxlocx, uint16_t *_maxlocy )
Parameter Descriptions
The following table describes the template and the function parameters.
| Parameter | Description |
|---|---|
| SRC_T | Input pixel type. 8-bit, unsigned, 1 channel (XF_8UC1), 16-bit, unsigned, 1 channel (XF_16UC1), 16-bit, signed, 1 channel (XF_16SC1), 32-bit, signed, 1 channel (XF_32SC1) are supported. |
| ROWS | Number of rows in the image being processed. |
| COLS | Number of columns in the image being processed. |
| 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. |
| XFCVDEPTH_IN | Depth of the input image. |
| _src | Input image |
| max_val | Maximum value in the image, of type int. |
| min_val | Minimum value in the image, of type int. |
| _minlocx | x-coordinate location of the first minimum value. |
| _minlocy | y-coordinate location of the first minimum value. |
| _maxlocx | x-coordinate location of the first maximum value. |
| _maxlocy | y-coordinate location of the first maximum value. |
Resource Utilization
The following table summarizes the resource utilization of the minMaxLoc function, generated using Vivado HLS 2019.1 tool for the Xczu9eg-ffvb1156-1-i-es1 FPGA, to process a grayscale HD (1080x1920) image.
| Operating Mode | Operating Frequency (MHz) | Utilization Estimate | ||||
|---|---|---|---|---|---|---|
| BRAM_18K | DSP_48Es | FF | LUT | CLB | ||
| 1 pixel | 300 | 0 | 3 | 451 | 398 | 86 |
| 8 pixel | 150 | 0 | 3 | 1049 | 1025 | 220 |
Performance Estimate
The following table summarizes the performance in different configurations, as generated using Vivado HLS 2019.1 tool for the Xilinx 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) | 1.69 |