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SIFT_create1

Features and matchingfunctionOpenCV 5.0.0
import { SIFT_create1 } from '@banou/opencv-wasm'

Use after await initOpenCV(). See the initialization and named imports guide.

ARGUMENTSnfeatures, nOctaveLayers, contrastThreshold, edgeThreshold
FUNCTIONSIFT_create1
RETURN TYPESIFT | null
Call structure. A void return can still write to destination arguments. The parameter descriptions define inputs, outputs and ownership.

Create SIFT with specified descriptorType.

Note: The contrast threshold will be divided by nOctaveLayers when the filtering is applied. When nOctaveLayers is set to default and if you want to use the value used in D. Lowe paper, 0.03, set this argument to 0.09.

SIFT_create1(nfeatures: number, nOctaveLayers: number, contrastThreshold: number, edgeThreshold: number, sigma: number, descriptorType: number, enable_precise_upscale: boolean): SIFT | null;
2 available overloads
SIFT_create1(nfeatures: number, nOctaveLayers: number, contrastThreshold: number, edgeThreshold: number, sigma: number, enable_precise_upscale: number): SIFT | null;
SIFT_create1(nfeatures: number, nOctaveLayers: number, contrastThreshold: number, edgeThreshold: number, sigma: number, descriptorType: number, enable_precise_upscale: boolean): SIFT | null;
nfeatures

The number of best features to retain. The features are ranked by their scores (measured in SIFT algorithm as the local contrast)

nOctaveLayers

The number of layers in each octave. 3 is the value used in D. Lowe paper. The number of octaves is computed automatically from the image resolution.

contrastThreshold

The contrast threshold used to filter out weak features in semi-uniform (low-contrast) regions. The larger the threshold, the less features are produced by the detector.

edgeThreshold

The threshold used to filter out edge-like features. Note that the its meaning is different from the contrastThreshold, i.e. the larger the edgeThreshold, the less features are filtered out (more features are retained).

sigma

The sigma of the Gaussian applied to the input image at the octave #0. If your image is captured with a weak camera with soft lenses, you might want to reduce the number.

enable_precise_upscale

Whether to enable precise upscaling in the scale pyramid, which maps index \texttt{x} to \texttt{2x}. This prevents localization bias. The option is disabled by default.

descriptorType

The type of descriptors. Only CV_32F and CV_8U are supported.

Returns

The SIFT | null result.

These signatures describe this package. Upstream documentation can mention optional backends that are absent from this build. Check runtime compatibility before choosing a backend or file format.