Start » Filter Reference » OpenCV » Video Analysis » cvCalcOpticalFlowPyrLK
Module: | OpenCV |
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Calculates an optical flow for a sparse feature set using the iterative Lucas-Kanade method with pyramids.
Name | Type | Range | Description | |
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inPrevImg | Image | First UINT8 single-channel or 3-channel input image. | ||
inNextImg | Image | Second input image of the same size and the same type as inPrevImg. | ||
inPrevPts | Point2DArray | Vector of 2D points for which the flow needs to be found. | ||
inNextPts | Point2DArray | Input vector of initial points positions. When inUseInitialFlow is true, the vector must have the same size as in the input. | ||
inWinWidth | Integer | 3 - | Width of the search window at each pyramid level. | |
inWinHeight | Integer | 3 - | Height of the search window at each pyramid level. | |
inMaxLevel | Integer | 0 - | 0-based maximal pyramid level number. If set to 0, pyramids are not used. If set to 1, two levels are used, and so on. | |
inTcEpsilon | Real | Criteria termination of the iterative process of corner refinement. Process stops when either after inTcMaxCount iterations or when the corner position moves by less than inTcEpsilon. | ||
inTcMaxCount | Integer | Criteria termination of the iterative process of corner refinement. Process stops when either after inTcMaxCount iterations or when the corner position moves by less than inTcEpsilon. | ||
inTcType | CvTerminationCriteria | Indicates which termination criteria will be used. | ||
inMinEigThreshold | Real | The algorithm calculates the minimum eigen value of a 2x2 normal matrix of optical flow equation. | ||
inUseInitialFlow | Bool | Use initial estimations stored in nextPts. If it is false, then prevPts is copied to nextPts and is considered as the initial estimate. | ||
outNextPts | Point2DArray | Output vector of 2D points containing the calculated new positions of input features in the second image. | ||
outStatus | IntegerArray | Output status vector. Each element of the vector is set to 1 if the flow for the corresponding features has been found. Otherwise, it is set to 0. | ||
outErr | RealArray | Output vector that contains the difference between patches around the original and moved points. |
Errors
This filter can throw an exception to report error. Read how to deal with errors in Error Handling.
List of possible exceptions:
Error type | Description |
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DomainError | inNextImg must have the same size, pixel type and depth as inPrevImg in cvCalcOpticalFlowPyrLK. |
DomainError | inPrevImg must be UINT8 single-channel or 3-channel image in cvCalcOpticalFlowPyrLK. |
DomainError | inPrevPts must have at least one point cvCalcOpticalFlowPyrLK. |
Complexity Level
This filter is available on Basic Complexity Level.