Accumulate - 2023.2 English

The accumulate function adds an image (src1) to the accumulator image (src2), and generates the accumulated result image (dst).

API Syntax

template<int SRC_T, int DST_T, int ROWS, int COLS, int NPC=1, int XFCVDEPTH_IN_1 = _XFCVDEPTH_DEFAULT, int XFCVDEPTH_IN_2 = _XFCVDEPTH_DEFAULT, int XFCVDEPTH_OUT_1 = _XFCVDEPTH_DEFAULT>
void accumulate (
xf::cv::Mat< SRC_T,  ROWS,  COLS,  NPC,  XFCVDEPTH_IN_1>& src1,
xf::cv::Mat< SRC_T,  ROWS,  COLS,  NPC,  XFCVDEPTH_IN_2>& src2,
xf::cv::Mat< DST_T,  ROWS,  COLS,  NPC,  XFCVDEPTH_OUT_1>& dst )

Parameter Descriptions

The following table describes the template and the function parameters.

Table 270 Table accumulate Parameter Description
Parameter	Description
SRC_T	Input pixel type. Only 8-bit, unsigned, 1 and 3 channels are supported (XF_8UC1 and XF_8UC3)
DST_T	Output pixel type. Only 16-bit, unsigned, 1 and 3 channels are supported (XF_16UC1 and XF_16UC3)
ROWS	Maximum height of input and output image.
COLS	Maximum width of input and output image. Recommend using a multiple of 8, for an 8-pixel operation.
NPC	Number of pixels to be processed per cycle; possible options are XF_NPPC1,XF_NPPC2,XF_NPPC4 and XF_NPPC8 for 1,2,4 pixel and 8 pixels operations respectively.
XFCVDEPTH_IN_1	Depth of the input image
XFCVDEPTH_IN_2	Depth of the input image
XFCVDEPTH_OUT_1	Depth of the output image
src1	Input image
src2	Input image
dst	Output image

Resource Utilization

The following table summarizes the resource utilization in different configurations, generated using Vivado HLS 2019.1 tool for the Xczu9eg-ffvb1156-1-i-es1, to process a grayscale HD (1080x1920) image.

Table 271 Table accumulate Function Resource Utilization Summary
Operating Mode	Operating Frequency (MHz)	Utilization Estimate
Operating Mode	Operating Frequency (MHz)	BRAM_18K	DSP_48Es	FF	LUT	CLB
1 Pixel	300	0	0	62	55	12
8 Pixel	150	0	0	389	285	61

The following table summarizes the resource utilization in different configurations, generated using Vivado HLS 2019.1 tool for the Xczu9eg-ffvb1156-1-i-es1, to process 4K 3 Channel image.

Table 272 Table 16. accumulate Function Resource Utilization Summary
Operating Mode	Operating Frequency (MHz)	Utilization Estimate
Operating Mode	Operating Frequency (MHz)	BRAM_18K	DSP_48Es	FF	LUT	CLB
1 Pixel	300	0	1	207	72	32

Performance Estimate

The following table summarizes the performance in different configurations, as generated using Vivado HLS 2019.1 tool for the Xczu9eg-ffvb1156-1-i-es1, to process a grayscale HD (1080x1920) image.

Table 273 Table 17. accumulate Function Performance Estimate Summary
Operating Mode	Latency Estimate
Operating Mode	Max Latency (ms)
1 pixel operation (300 MHz)	6.9
8 pixel operation (150 MHz)	1.7

Deviation from OpenCV

In OpenCV the accumulated image is stored in the second input image. The src2 image acts as both input and output, as shown below:

Whereas, in the Vitis Vision implementation, the accumulated image is stored separately, as shown below: