ORBFeatureOrientation.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_CV_DETECTOR_ORB_FEATURE_ORIENTATION_H
#define META_OCEAN_CV_DETECTOR_ORB_FEATURE_ORIENTATION_H
 
#include "ocean/cv/detector/Detector.h"
#include "ocean/cv/detector/ORBFeature.h"
 
#include "ocean/base/Worker.h"
 
#include "ocean/cv/FrameInterpolatorBilinear.h"
 
namespace Ocean
{
 
namespace CV
{
 
namespace Detector
{
 
/**
 * This class implements all necessary functions to calculate the orientation of an ORB features.
 * @ingroup cvdetector
 */
class OCEAN_CV_DETECTOR_EXPORT ORBFeatureOrientation
{
    public:
 
        /**
         * Determines the orientation for all given feature points based on the intensity centroid of a patch around the feature positions.
         * A image patch with size 31x31 pixels is used to calculate the orientation.
         * @param linedIntegralFrame Pointer to the lined integral frame of the frame where the feature points were detected; must be an integral frame for an 8 bit frame
         * @param width The width of the original frame in pixel (not the width of the lined-integral frame), with range [31, infinity)
         * @param height The height of the original frame in pixel (not the height of the lined-integral frame), with range [31, infinity)
         * @param featurePoints Feature points to determine the orientation for
         * @param worker Optional worker object to distribute the computation to several CPU cores
         */
        static void determineFeatureOrientation(const unsigned int* linedIntegralFrame, const unsigned int width, const unsigned int height, ORBFeatures& featurePoints, Worker* worker = nullptr);
 
    protected:
 
        /**
         * Determines the orientation for all given feature points based on the intensity centroid of a patch around the feature positions.
         * A image patch with size 31x31 pixels is used to calculate the orientation.
         * @param linedIntegralFrame Pointer to the lined integral frame of the frame where the feature points were detected; must be an integral frame for an 8 bit frame
         * @param width The width of the original frame in pixel (not the width of the lined-integral frame), with range [31, infinity)
         * @param height The height of the original frame in pixel (not the height of the lined-integral frame), with range [31, infinity)
         * @param featurePoints Feature points to determine the orientation for
         * @param startIndex First index of the feature point vector to be handled
         * @param range Number of feature points to be handled
         */
        static void determineFeatureOrientationSubset(const unsigned int* linedIntegralFrame, const unsigned int width, const unsigned int height, ORBFeatures* const featurePoints, const unsigned int startIndex, const unsigned int range);
 
        /**
         * Determines the orientation for a given feature point based on the intensity centroid of a patch around the feature position.
         * A image patch with size 31x31 pixels is used to calculate the orientation.
         * @param linedIntegralFrame Pointer to the lined integral frame of the frame where the feature points were detected; must be an integral frame for an 8 bit frame
         * @param width The width of the original frame in pixel (not the width of the lined-integral frame), with range [31, infinity)
         * @param height The height of the original frame in pixel (not the height of the lined-integral frame), with range [31, infinity)
         * @param position The 2D position of the feature, with pixel center PC_CENTER, with range (15, width - 15)x(15, height - 15)
         * @return Orientation angle in radian with range [0, 2*PI)
         */
        static Scalar determineFeatureOrientation31(const unsigned int* linedIntegralFrame, const unsigned int width, const unsigned int height, const Vector2& position);
};
 
}
 
}
 
}
 
#endif // META_OCEAN_CV_DETECTOR_ORB_FEATURE_ORIENTATION_H