Package org.opencv.features2d

Class BOWImgDescriptorExtractor

java.lang.Object
org.opencv.features2d.BOWImgDescriptorExtractor
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.

  • Field Details

    • nativeObj

      protected final long nativeObj

  • Constructor Details

    • BOWImgDescriptorExtractor

      protected BOWImgDescriptorExtractor(long addr)

    • BOWImgDescriptorExtractor

      public BOWImgDescriptorExtractor(Feature2D dextractor, DescriptorMatcher dmatcher)
      The constructor.
      Parameters:
      dextractor - Descriptor extractor that is used to compute descriptors for an input image and its keypoints.
      dmatcher - Descriptor matcher that is used to find the nearest word of the trained vocabulary for each keypoint descriptor of the image.

  • Method Details

    • getNativeObjAddr

      public long getNativeObjAddr()

    • __fromPtr__

      public static BOWImgDescriptorExtractor __fromPtr__(long addr)

    • 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).

    • getVocabulary

      public Mat getVocabulary()
      Returns the set vocabulary.
      Returns:
      automatically generated

    • compute

      public void compute(Mat image, MatOfKeyPoint keypoints, Mat imgDescriptor)
      Parameters:
      image - automatically generated
      keypoints - automatically generated
      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.

    • descriptorSize

      public int descriptorSize()
      Returns an image descriptor size if the vocabulary is set. Otherwise, it returns 0.
      Returns:
      automatically generated

    • descriptorType

      public int descriptorType()
      Returns an image descriptor type.
      Returns:
      automatically generated

    • finalize

      protected void finalize() throws Throwable
      Overrides:
      finalize in class Object
      Throws:
      Throwable