Overview | Package | Class | Tree | Index | Help

OpenCV 2.4.3.1
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## org.opencv.features2d
Class DescriptorExtractor

    java.lang.Object
      org.opencv.features2d.DescriptorExtractor

    public class DescriptorExtractor

extends java.lang.Object

Abstract base class for computing descriptors for image keypoints.

class CV_EXPORTS DescriptorExtractor ``

// C++ code:

public:

virtual ~DescriptorExtractor();

void compute(const Mat& image, vector& keypoints,

Mat& descriptors) const;

void compute(const vector& images, vector >& keypoints,

vector& descriptors) const;

virtual void read(const FileNode&);

virtual void write(FileStorage&) const;

virtual int descriptorSize() const = 0;

virtual int descriptorType() const = 0;

static Ptr create(const string& descriptorExtractorType);

protected:...

};

In this interface, a keypoint descriptor can be represented as a

dense, fixed-dimension vector of a basic type. Most descriptors follow this pattern as it simplifies computing distances between descriptors. Therefore, a collection of descriptors is represented as "Mat", where each row is a keypoint descriptor.

See Also:
  org.opencv.features2d.DescriptorExtractor : public Algorithm

Field Summary
`static int` | `BRIEF`
`static int` | `BRISK`
`static int` | `FREAK`
`protected long` | `nativeObj`
`static int` | `OPPONENT_BRIEF`
`static int` | `OPPONENT_BRISK`
`static int` | `OPPONENT_FREAK`
`static int` | `OPPONENT_ORB`
`static int` | `OPPONENT_SIFT`
`static int` | `OPPONENT_SURF`
`static int` | `ORB`
`static int` | `SIFT`
`static int` | `SURF`

Constructor Summary
`protected` | `DescriptorExtractor(long addr)`

Method Summary
`void` | `compute(java.util.List<Mat> images, java.util.List<MatOfKeyPoint> keypoints, java.util.List<Mat> descriptors)` Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant).
`void` | `compute(Mat image, MatOfKeyPoint keypoints, Mat descriptors)` Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant).
`static DescriptorExtractor` | `create(int extractorType)` Creates a descriptor extractor by name.
`int` | `descriptorSize()`
`int` | `descriptorType()`
`boolean` | `empty()`
`protected void` | `finalize()`
`void` | `read(java.lang.String fileName)`
`void` | `write(java.lang.String fileName)`

Methods inherited from class java.lang.Object
`clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### BRIEF

    public static final int BRIEF

See Also:
  Constant Field Values

### BRISK

    public static final int BRISK

See Also:
  Constant Field Values

### FREAK

    public static final int FREAK

See Also:
  Constant Field Values

### nativeObj

    protected final long nativeObj

### OPPONENT_BRIEF

    public static final int OPPONENT_BRIEF

See Also:
  Constant Field Values

### OPPONENT_BRISK

    public static final int OPPONENT_BRISK

See Also:
  Constant Field Values

### OPPONENT_FREAK

    public static final int OPPONENT_FREAK

See Also:
  Constant Field Values

### OPPONENT_ORB

    public static final int OPPONENT_ORB

See Also:
  Constant Field Values

### OPPONENT_SIFT

    public static final int OPPONENT_SIFT

See Also:
  Constant Field Values

### OPPONENT_SURF

    public static final int OPPONENT_SURF

See Also:
  Constant Field Values

### ORB

    public static final int ORB

See Also:
  Constant Field Values

### SIFT

    public static final int SIFT

See Also:
  Constant Field Values

### SURF

    public static final int SURF

See Also:
  Constant Field Values

Constructor Detail

### DescriptorExtractor

    protected DescriptorExtractor(long addr)

Method Detail

### compute

    public void compute(java.util.List<Mat> images,
                        java.util.List<MatOfKeyPoint> keypoints,
                        java.util.List<Mat> descriptors)

  Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant).

  Parameters:
    `images` - Image set.
    `keypoints` - Input collection of keypoints. Keypoints for which a descriptor cannot be computed are removed. Sometimes new keypoints can be added, for example: `SIFT` duplicates keypoint with several dominant orientations (for each orientation).
    `descriptors` - Computed descriptors. In the second variant of the method `descriptors[i]` are descriptors computed for a `keypoints[i]". Row` j`is the` keypoints`(or` keypoints[i]`) is the descriptor for keypoint` j"-th keypoint.
  See Also:
    org.opencv.features2d.DescriptorExtractor.compute

### compute

    public void compute(Mat image,
                        MatOfKeyPoint keypoints,
                        Mat descriptors)

  Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant).

  Parameters:
    `image` - Image.
    `keypoints` - Input collection of keypoints. Keypoints for which a descriptor cannot be computed are removed. Sometimes new keypoints can be added, for example: `SIFT` duplicates keypoint with several dominant orientations (for each orientation).
    `descriptors` - Computed descriptors. In the second variant of the method `descriptors[i]` are descriptors computed for a `keypoints[i]". Row` j`is the` keypoints`(or` keypoints[i]`) is the descriptor for keypoint` j"-th keypoint.
  See Also:
    org.opencv.features2d.DescriptorExtractor.compute

### create

    public static DescriptorExtractor create(int extractorType)

  Creates a descriptor extractor by name.

  The current implementation supports the following types of a descriptor extractor:

  - `"SIFT"` -- "SIFT"
  - `"SURF"` -- "SURF"
  - `"ORB"` -- "ORB"
  - `"BRIEF"` -- "BriefDescriptorExtractor"

  A combined format is also supported: descriptor extractor adapter name (`"Opponent"` -- "OpponentColorDescriptorExtractor") + descriptor extractor name (see above), for example: `"OpponentSIFT"`.

  Parameters:
    `extractorType` - a extractorType
  See Also:
    org.opencv.features2d.DescriptorExtractor.create

### descriptorSize

    public int descriptorSize()

### descriptorType

    public int descriptorType()

### empty

    public boolean empty()

### finalize

    protected void finalize()
                     throws java.lang.Throwable

  Overrides:
    `finalize` in class `java.lang.Object`
  Throws:
    `java.lang.Throwable`

### read

    public void read(java.lang.String fileName)

### write

    public void write(java.lang.String fileName)

Overview | Package | Class | Tree | Index | Help

Official OpenCV 2.4 Documentation
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD