Sift
Function Usage
Constructor of the Sift class. It serves as the implementation class of image scale invariant feature conversion, mainly opens feature point extraction and compute APIs. Only Atlas 200I A2 accelerator module (20 TOPS, 12 GB) supports this function.
Prototype
1 | explicit Sift::Sift(int nFeatures = 0, int nOctaveLayers = 3, double contrastThreshold = 0.04, double edgeThreshold = 10, double sigma = 1.6, int descriptorType = CV_32F);// The std::runtime_error exception is thrown when the construction fails. |
Parameters
Parameter |
Input/Output |
Description |
|---|---|---|
nFeatures |
Input |
Sorts extracted feature points and returns the best first nFeatures bits (including parallel bits). The default value is 0, indicating that all feature points are extracted. The number of identified feature points is the returned number of feature points. |
nOctaveLayers |
Input |
Number of middle layers in each group of images in the scale space. The default value is 3. Only the default value is supported. If other values are passed, the construction fails and the std::runtime_error exception is thrown.
|
contrastThreshold |
Input |
Threshold for filtering feature points. The default value is 0.04, and the value range is [0.0, 20.0]. |
edgeThreshold |
Input |
Threshold for filtering edge effects. The default value is 10, and the value range is [0.0, 1000.0]. |
sigma |
Input |
Initial blur scale, which is the Gaussian filtering coefficient of the image at layer 0 of the Gaussian pyramid. The default value is 1.6. Only the default value is supported. If other values are passed, the construction fails and the std::runtime_error exception is thrown. |
descriptorType |
Input |
Data type of the feature descriptor. The default value is CV_32F. The following data types are supported:
|