Class cv::cuda::NvidiaOpticalFlow_2_0

Class for computing the optical flow vectors between two images using NVIDIA Optical Flow hardware and Optical Flow SDK 2.0. View details

#include <opencv2/cudaoptflow.hpp>

Collaboration diagram for cv::cuda::NvidiaOpticalFlow_2_0:

Public Types

enum NVIDIA_OF_HINT_VECTOR_GRID_SIZE {
    NV_OF_HINT_VECTOR_GRID_SIZE_UNDEFINED,
    NV_OF_HINT_VECTOR_GRID_SIZE_1 = 1,
    NV_OF_HINT_VECTOR_GRID_SIZE_2 = 2,
    NV_OF_HINT_VECTOR_GRID_SIZE_4 = 4,
    NV_OF_HINT_VECTOR_GRID_SIZE_8 = 8,
    NV_OF_HINT_VECTOR_GRID_SIZE_MAX
}

enum NVIDIA_OF_OUTPUT_VECTOR_GRID_SIZE {
    NV_OF_OUTPUT_VECTOR_GRID_SIZE_UNDEFINED,
    NV_OF_OUTPUT_VECTOR_GRID_SIZE_1 = 1,
    NV_OF_OUTPUT_VECTOR_GRID_SIZE_2 = 2,
    NV_OF_OUTPUT_VECTOR_GRID_SIZE_4 = 4,
    NV_OF_OUTPUT_VECTOR_GRID_SIZE_MAX
}

enum NVIDIA_OF_PERF_LEVEL {
    NV_OF_PERF_LEVEL_UNDEFINED,
    NV_OF_PERF_LEVEL_SLOW = 5,
    NV_OF_PERF_LEVEL_MEDIUM = 10,
    NV_OF_PERF_LEVEL_FAST = 20,
    NV_OF_PERF_LEVEL_MAX
}

Public Member Functions

Public Member Functions inherited from cv::cuda::NvidiaHWOpticalFlow

Return	Name	Description
void	calc(     InputArray inputImage,     InputArray referenceImage,     InputOutputArray flow,     Stream & stream = Stream::Null(),     InputArray hint = cv::noArray(),     OutputArray cost = cv::noArray() )	Calculates Optical Flow using NVIDIA Optical Flow SDK.
void	collectGarbage()	Releases all buffers, contexts and device pointers.
int	getGridSize()	Returns grid size of output buffer as per the hardware’s capability.

Public Member Functions inherited from cv::Algorithm

Return	Name	Description
	Algorithm()
	~Algorithm()
void	clear()	Clears the algorithm state.
bool	empty()	Returns true if the Algorithm is empty (e.g. in the very beginning or after unsuccessful read.
String	getDefaultName()
void	read(const FileNode & fn)	Reads algorithm parameters from a file storage.
void	save(const String & filename)
void	write(     const Ptr< FileStorage > & fs,     const String & name = String() )
void	write(FileStorage & fs)	Stores algorithm parameters in a file storage.
void	write(     FileStorage & fs,     const String & name )

Static Public Member Functions

Static Public Member Functions inherited from cv::Algorithm

Return	Name	Description
static Ptr< _Tp >	load(     const String & filename,     const String & objname = String() )	Loads algorithm from the file.
static Ptr< _Tp >	loadFromString(     const String & strModel,     const String & objname = String() )	Loads algorithm from a String.
static Ptr< _Tp >	read(const FileNode & fn)	Reads algorithm from the file node.

Additional Inherited Members

Protected Member Functions inherited from cv::Algorithm

Return	Name	Description
void	writeFormat(FileStorage & fs)

Detailed Description

Class for computing the optical flow vectors between two images using NVIDIA Optical Flow hardware and Optical Flow SDK 2.0.

Note

• A sample application demonstrating the use of NVIDIA Optical Flow can be found at opencv_contrib_source_code/modules/cudaoptflow/samples/nvidia_optical_flow.cpp

• An example application comparing accuracy and performance of NVIDIA Optical Flow with other optical flow algorithms in OpenCV can be found at opencv_contrib_source_code/modules/cudaoptflow/samples/optical_flow.cpp

Member Enumeration Documentation

enum NVIDIA_OF_HINT_VECTOR_GRID_SIZE

NV_OF_HINT_VECTOR_GRID_SIZE_UNDEFINED
NV_OF_HINT_VECTOR_GRID_SIZE_1	Hint buffer grid size is 1x1.
NV_OF_HINT_VECTOR_GRID_SIZE_2	Hint buffer grid size is 2x2.
NV_OF_HINT_VECTOR_GRID_SIZE_4	Hint buffer grid size is 4x4.
NV_OF_HINT_VECTOR_GRID_SIZE_8	Hint buffer grid size is 8x8.
NV_OF_HINT_VECTOR_GRID_SIZE_MAX

enum NVIDIA_OF_OUTPUT_VECTOR_GRID_SIZE

NV_OF_OUTPUT_VECTOR_GRID_SIZE_UNDEFINED
NV_OF_OUTPUT_VECTOR_GRID_SIZE_1	Output buffer grid size is 1x1
NV_OF_OUTPUT_VECTOR_GRID_SIZE_2	Output buffer grid size is 2x2
NV_OF_OUTPUT_VECTOR_GRID_SIZE_4	Output buffer grid size is 4x4
NV_OF_OUTPUT_VECTOR_GRID_SIZE_MAX

enum NVIDIA_OF_PERF_LEVEL

NV_OF_PERF_LEVEL_UNDEFINED
NV_OF_PERF_LEVEL_SLOW	Slow perf level results in lowest performance and best quality
NV_OF_PERF_LEVEL_MEDIUM	Medium perf level results in low performance and medium quality
NV_OF_PERF_LEVEL_FAST	Fast perf level results in high performance and low quality
NV_OF_PERF_LEVEL_MAX

Member Function Documentation

convertToFloat()

void cv::cuda::NvidiaOpticalFlow_2_0::convertToFloat(
InputArray flow,
InputOutputArray floatFlow )

convertToFloat() helper function converts the hardware-generated flow vectors to floating point representation (1 flow vector for gridSize). gridSize can be queried via function getGridSize().

Parameters

• flow — Buffer of type CV_16FC2 containing flow vectors generated by calc().

• floatFlow — Buffer of type CV_32FC2, containing flow vectors in floating point representation, each flow vector for 1 pixel per gridSize, in the pitch-linear layout.

create()

static Ptr< NvidiaOpticalFlow_2_0 > cv::cuda::NvidiaOpticalFlow_2_0::create(
cv::Size imageSize,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_PERF_LEVEL perfPreset = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_PERF_LEVEL_SLOW,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_OUTPUT_VECTOR_GRID_SIZE outputGridSize = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_OUTPUT_VECTOR_GRID_SIZE_1,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_HINT_VECTOR_GRID_SIZE hintGridSize = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_HINT_VECTOR_GRID_SIZE_1,
bool enableTemporalHints = false,
bool enableExternalHints = false,
bool enableCostBuffer = false,
int gpuId = 0,
Stream & inputStream = Stream::Null(),
Stream & outputStream = Stream::Null() )

Instantiate NVIDIA Optical Flow.

Parameters

• imageSize — Size of input image in pixels.

• perfPreset — Optional parameter. Refer NV OF SDK documentation for details about presets. Defaults to NV_OF_PERF_LEVEL_SLOW.

• outputGridSize — Optional parameter. Refer NV OF SDK documentation for details about output grid sizes. Defaults to NV_OF_OUTPUT_VECTOR_GRID_SIZE_1.

• hintGridSize — Optional parameter. Refer NV OF SDK documentation for details about hint grid sizes. Defaults to NV_OF_HINT_VECTOR_GRID_SIZE_1.

• enableTemporalHints — Optional parameter. Flag to enable temporal hints. When set to true, the hardware uses the flow vectors generated in previous call to calc() as internal hints for the current call to calc(). Useful when computing flow vectors between successive video frames. Defaults to false.

• enableExternalHints — Optional Parameter. Flag to enable passing external hints buffer to calc(). Defaults to false.

• enableCostBuffer — Optional Parameter. Flag to enable cost buffer output from calc(). Defaults to false.

• gpuId — Optional parameter to select the GPU ID on which the optical flow should be computed. Useful in multi-GPU systems. Defaults to 0.

• inputStream — Optical flow algorithm may optionally involve cuda preprocessing on the input buffers. The input cuda stream can be used to pipeline and synchronize the cuda preprocessing tasks with OF HW engine. If input stream is not set, the execute function will use default stream which is NULL stream;

• outputStream — Optical flow algorithm may optionally involve cuda post processing on the output flow vectors. The output cuda stream can be used to pipeline and synchronize the cuda post processing tasks with OF HW engine. If output stream is not set, the execute function will use default stream which is NULL stream;

create()

static Ptr< NvidiaOpticalFlow_2_0 > cv::cuda::NvidiaOpticalFlow_2_0::create(
cv::Size imageSize,
std::vector< Rect > roiData,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_PERF_LEVEL perfPreset = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_PERF_LEVEL_SLOW,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_OUTPUT_VECTOR_GRID_SIZE outputGridSize = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_OUTPUT_VECTOR_GRID_SIZE_1,
cv::cuda::NvidiaOpticalFlow_2_0::NVIDIA_OF_HINT_VECTOR_GRID_SIZE hintGridSize = cv::cuda::NvidiaOpticalFlow_2_0::NV_OF_HINT_VECTOR_GRID_SIZE_1,
bool enableTemporalHints = false,
bool enableExternalHints = false,
bool enableCostBuffer = false,
int gpuId = 0,
Stream & inputStream = Stream::Null(),
Stream & outputStream = Stream::Null() )

Instantiate NVIDIA Optical Flow with ROI Feature.

Parameters

• imageSize — Size of input image in pixels.

• roiData — Pointer to ROI data.

• perfPreset — Optional parameter. Refer NV OF SDK documentation for details about presets. Defaults to NV_OF_PERF_LEVEL_SLOW.

• outputGridSize — Optional parameter. Refer NV OF SDK documentation for details about output grid sizes. Defaults to NV_OF_OUTPUT_VECTOR_GRID_SIZE_1.

• hintGridSize — Optional parameter. Refer NV OF SDK documentation for details about hint grid sizes. Defaults to NV_OF_HINT_VECTOR_GRID_SIZE_1.

• enableTemporalHints — Optional parameter. Flag to enable temporal hints. When set to true, the hardware uses the flow vectors generated in previous call to calc() as internal hints for the current call to calc(). Useful when computing flow vectors between successive video frames. Defaults to false.

• enableExternalHints — Optional Parameter. Flag to enable passing external hints buffer to calc(). Defaults to false.

• enableCostBuffer — Optional Parameter. Flag to enable cost buffer output from calc(). Defaults to false.

• gpuId — Optional parameter to select the GPU ID on which the optical flow should be computed. Useful in multi-GPU systems. Defaults to 0.

• inputStream — Optical flow algorithm may optionally involve cuda preprocessing on the input buffers. The input cuda stream can be used to pipeline and synchronize the cuda preprocessing tasks with OF HW engine. If input stream is not set, the execute function will use default stream which is NULL stream;

• outputStream — Optical flow algorithm may optionally involve cuda post processing on the output flow vectors. The output cuda stream can be used to pipeline and synchronize the cuda post processing tasks with OF HW engine. If output stream is not set, the execute function will use default stream which is NULL stream;

Source file

The documentation for this class was generated from the following file:

• opencv2/cudaoptflow.hpp