Degamma - 2023.2 English

API Syntax

Degamma also known as linearization is typically designed to linearize the input from sensor (or any pre-processing IP) in order to facilitate ISP processing that operates on linear domain, such as noise reduction. While non-linearization comes in several forms, this module is served to linearize only simple curves.

This implementaion supports Bayer Raw data of 8, 10, 12, 16 bits per pixel with maximum 64 knee points PWL mapping.

template <int SRC_T,
      int DST_T,
      int ROWS,
      int COLS,
      int NPC,
      int XFCVDEPTH_IN = _XFCVDEPTH_DEFAULT,
      int XFCVDEPTH_OUT = _XFCVDEPTH_DEFAULT,
      int N>
void degamma(xf::cv::Mat<SRC_T, ROWS, COLS, NPC, XFCVDEPTH_IN>& src,
         xf::cv::Mat<DST_T, ROWS, COLS, NPC, XFCVDEPTH_OUT>& dst,
         ap_ufixed<32, 16> params[3][N][3],
         unsigned short bayerp)

The following table describes the template and the function parameters.

Table 487 Table HDR Decompand Parameter Description
Parameter	Description
SRC_T \| Input Pixel type. The current supported pixel value is XF_8UC1 and XF_16UC1
DST_T \| Output Pixel type. The current supported pixel value is XF_8UC1 and XF_16UC1
ROWS	Maximum height of the image that hardware kernel must be built for
COLS	Maximum width of the image that hardware kernel must be built for
NPC	Number of Pixels to be processed per cycle. NPPC1 and NPPC2 are supported.
XFCVDEPTH_IN	Depth of Input Image
XFCVDEPTH_OUT	Depth of Output Image
N	Configurable number of knee points
src	Input Image
dst	Output Image
params	array containing upper limit, slope and intercept of linear equations for Red, Green and Blue colours.
bayerp	Input Bayer pattern. XF_BAYER_BG, XF_BAYER_GB, XF_BAYER_GR and XF_BAYER_RG are the supported values.

Resource Utilization

The following table summarizes the resource utilization in different configurations, generated using Vitis HLS 2022.2 tool for the xcu200-fsgd2104-2-e, to process a FHD Bayer image.

Table 488 Table Degamma Resource Utilization Summary
Operating Mode	Operating Frequency (MHz)	Utilization Estimate
Operating Mode	Operating Frequency (MHz)	BRAM_18K	DSP	FF	LUT	URAM
1 Pixel	300	0	4	2187	2082	0
2 Pixel	300	0	8	4265 \| 4078		0

Performance Estimate

The following table summarizes the performance estimates in different configurations, generated using Vitis HLS 2022.2 tool for the xcu200-fsgd2104-2-e, to process a FHD Bayer image.

Table 489 Table Degamma Performance Estimate Summary
Operating Mode	Operating Frequency (MHz)	Latency Estimate
Operating Mode	Operating Frequency (MHz)	Max (ms)
1 pixel	300	7.2
2 pixel	300	3.6