// This implementation of, and any deviation from, the original algorithm as
// proposed by Ziegler et al. is not endorsed by Ziegler et al. nor does it
// claim to represent their definition of locally uniform comparison image
// descriptor. The original LUCID algorithm as proposed by Ziegler et al. remains
// the property of its respective authors. This implementation is an adaptation of
// said algorithm and contributed to OpenCV by Str3iber.

// References:
// Ziegler, Andrew, Eric Christiansen, David Kriegman, and Serge J. Belongie.
// "Locally uniform comparison image descriptor." In Advances in Neural Information
// Processing Systems, pp. 1-9. 2012.

/*
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copy or use the software.


                          License Agreement
               For Open Source Computer Vision Library
                       (3-clause BSD License)

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

  * Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.

  * Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
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  * Neither the names of the copyright holders nor the names of the contributors
    may be used to endorse or promote products derived from this software
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This software is provided by the copyright holders and contributors "as is" and
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*/

#include "precomp.hpp"

namespace cv {
    namespace xfeatures2d {
        /*!
         LUCID implementation
         */
        class LUCIDImpl : public LUCID {
            public:
                /** Constructor
                 * @param lucid_kernel kernel for descriptor construction, where 1=3x3, 2=5x5, 3=7x7 and so forth
                 * @param blur_kernel kernel for blurring image prior to descriptor construction, where 1=3x3, 2=5x5, 3=7x7 and so forth
                 */
                LUCIDImpl(const int lucid_kernel = 1, const int blur_kernel = 2);

                /** returns the descriptor length */
                virtual int descriptorSize() const;

                /** returns the descriptor type */
                virtual int descriptorType() const;

                /** returns the default norm type */
                virtual int defaultNorm() const;

                virtual void compute(InputArray _src, std::vector<KeyPoint> &keypoints, OutputArray _desc);

            protected:
                int l_kernel, b_kernel;
        };

        Ptr<LUCID> LUCID::create(const int lucid_kernel, const int blur_kernel) {
            return makePtr<LUCIDImpl>(lucid_kernel, blur_kernel);
        }

        LUCIDImpl::LUCIDImpl(const int lucid_kernel, const int blur_kernel) {
            l_kernel = lucid_kernel;
            b_kernel = blur_kernel*2+1;
        }

        int LUCIDImpl::descriptorSize() const {
            return (l_kernel*2+1)*(l_kernel*2+1)*3;
        }

        int LUCIDImpl::descriptorType() const {
            return CV_8UC1;
        }

        int LUCIDImpl::defaultNorm() const {
            return NORM_HAMMING;
        }

        // gliese581h suggested filling a cv::Mat with descriptors to enable BFmatcher compatibility
        // speed-ups and enhancements by gliese581h
        void LUCIDImpl::compute(InputArray _src, std::vector<KeyPoint> &keypoints, OutputArray _desc) {
            if (_src.getMat().empty())
                return;

            Mat_<Vec3b> src;

            blur(_src.getMat(), src, cv::Size(b_kernel, b_kernel));

            int x, y, j, d, p, m = (l_kernel*2+1)*(l_kernel*2+1)*3, width = src.cols, height = src.rows, r, c;

            Mat_<uchar> desc(static_cast<int>(keypoints.size()), m);

            for (std::size_t i = 0; i < keypoints.size(); ++i) {
                x = static_cast<int>(keypoints[i].pt.x)-l_kernel, y = static_cast<int>(keypoints[i].pt.y)-l_kernel, d = x+2*l_kernel, p = y+2*l_kernel, j = x, r = static_cast<int>(i), c = 0;

                while (x <= d) {
                    Vec3b &pix = src((y < 0 ? height+y : y >= height ? y-height : y), (x < 0 ? width+x : x >= width ? x-width : x));

                    desc(r, c++) = pix[0];
                    desc(r, c++) = pix[1];
                    desc(r, c++) = pix[2];

                    ++x;
                    if (x > d) {
                        if (y < p) {
                            ++y;
                            x = j;
                        }
                        else
                            break;
                    }
                }
            }

            if (_desc.needed())
                sort(desc, _desc, SORT_EVERY_ROW | SORT_ASCENDING);
        }
    }
} // END NAMESPACE CV