Package org.opencv.features2d
Class BOWImgDescriptorExtractor
- java.lang.Object
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- org.opencv.features2d.BOWImgDescriptorExtractor
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public class BOWImgDescriptorExtractor extends Object
Class to compute an image descriptor using the *bag of visual words*. Such a computation consists of the following steps: 1. Compute descriptors for a given image and its keypoints set. 2. Find the nearest visual words from the vocabulary for each keypoint descriptor. 3. Compute the bag-of-words image descriptor as is a normalized histogram of vocabulary words encountered in the image. The i-th bin of the histogram is a frequency of i-th word of the vocabulary in the given image.
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Field Summary
Fields Modifier and Type Field Description protected longnativeObj
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Constructor Summary
Constructors Modifier Constructor Description protectedBOWImgDescriptorExtractor(long addr)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static BOWImgDescriptorExtractor__fromPtr__(long addr)voidcompute(Mat image, MatOfKeyPoint keypoints, Mat imgDescriptor)intdescriptorSize()Returns an image descriptor size if the vocabulary is set.intdescriptorType()Returns an image descriptor type.protected voidfinalize()longgetNativeObjAddr()MatgetVocabulary()Returns the set vocabulary.voidsetVocabulary(Mat vocabulary)Sets a visual vocabulary.
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Method Detail
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getNativeObjAddr
public long getNativeObjAddr()
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__fromPtr__
public static BOWImgDescriptorExtractor __fromPtr__(long addr)
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getVocabulary
public Mat getVocabulary()
Returns the set vocabulary.- Returns:
- automatically generated
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descriptorSize
public int descriptorSize()
Returns an image descriptor size if the vocabulary is set. Otherwise, it returns 0.- Returns:
- automatically generated
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descriptorType
public int descriptorType()
Returns an image descriptor type.- Returns:
- automatically generated
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compute
public void compute(Mat image, MatOfKeyPoint keypoints, Mat imgDescriptor)
- Parameters:
imgDescriptor- Computed output image descriptor. pointIdxsOfClusters[i] are keypoint indices that belong to the i -th cluster (word of vocabulary) returned if it is non-zero.image- automatically generatedkeypoints- automatically generated
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setVocabulary
public void setVocabulary(Mat vocabulary)
Sets a visual vocabulary.- Parameters:
vocabulary- Vocabulary (can be trained using the inheritor of BOWTrainer ). Each row of the vocabulary is a visual word (cluster center).
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