root/modules/photo/src/calibrate.cpp

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DEFINITIONS

This source file includes following definitions.
  1. w
  2. process
  3. getSamples
  4. setSamples
  5. getLambda
  6. setLambda
  7. getRandom
  8. setRandom
  9. write
  10. read
  11. createCalibrateDebevec
  12. weight
  13. process
  14. getMaxIter
  15. setMaxIter
  16. getThreshold
  17. setThreshold
  18. getRadiance
  19. write
  20. read
  21. createCalibrateRobertson

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#include "precomp.hpp"
#include "opencv2/photo.hpp"
#include "opencv2/imgproc.hpp"
//#include "opencv2/highgui.hpp"
#include "hdr_common.hpp"

namespace cv
{

class CalibrateDebevecImpl : public CalibrateDebevec
{
public:
    CalibrateDebevecImpl(int _samples, float _lambda, bool _random) :
        name("CalibrateDebevec"),
        samples(_samples),
        lambda(_lambda),
        random(_random),
        w(tringleWeights())
    {
    }

    void process(InputArrayOfArrays src, OutputArray dst, InputArray _times)
    {
        std::vector<Mat> images;
        src.getMatVector(images);
        Mat times = _times.getMat();

        CV_Assert(images.size() == times.total());
        checkImageDimensions(images);
        CV_Assert(images[0].depth() == CV_8U);

        int channels = images[0].channels();
        int CV_32FCC = CV_MAKETYPE(CV_32F, channels);

        dst.create(LDR_SIZE, 1, CV_32FCC);
        Mat result = dst.getMat();

        std::vector<Point> sample_points;
        if(random) {
            for(int i = 0; i < samples; i++) {
                sample_points.push_back(Point(rand() % images[0].cols, rand() % images[0].rows));
            }
        } else {
            int x_points = static_cast<int>(sqrt(static_cast<double>(samples) * images[0].cols / images[0].rows));
            int y_points = samples / x_points;
            int step_x = images[0].cols / x_points;
            int step_y = images[0].rows / y_points;

            for(int i = 0, x = step_x / 2; i < x_points; i++, x += step_x) {
                for(int j = 0, y = step_y / 2; j < y_points; j++, y += step_y) {
                    if( 0 <= x && x < images[0].cols &&
                        0 <= y && y < images[0].rows )
                        sample_points.push_back(Point(x, y));
                }
            }
        }

        std::vector<Mat> result_split(channels);
        for(int channel = 0; channel < channels; channel++) {
            Mat A = Mat::zeros((int)sample_points.size() * (int)images.size() + LDR_SIZE + 1, LDR_SIZE + (int)sample_points.size(), CV_32F);
            Mat B = Mat::zeros(A.rows, 1, CV_32F);

            int eq = 0;
            for(size_t i = 0; i < sample_points.size(); i++) {
                for(size_t j = 0; j < images.size(); j++) {

                    int val = images[j].ptr()[3*(sample_points[i].y * images[j].cols + sample_points[i].x) + channel];
                    A.at<float>(eq, val) = w.at<float>(val);
                    A.at<float>(eq, LDR_SIZE + (int)i) = -w.at<float>(val);
                    B.at<float>(eq, 0) = w.at<float>(val) * log(times.at<float>((int)j));
                    eq++;
                }
            }
            A.at<float>(eq, LDR_SIZE / 2) = 1;
            eq++;

            for(int i = 0; i < 254; i++) {
                A.at<float>(eq, i) = lambda * w.at<float>(i + 1);
                A.at<float>(eq, i + 1) = -2 * lambda * w.at<float>(i + 1);
                A.at<float>(eq, i + 2) = lambda * w.at<float>(i + 1);
                eq++;
            }
            Mat solution;
            solve(A, B, solution, DECOMP_SVD);
            solution.rowRange(0, LDR_SIZE).copyTo(result_split[channel]);
        }
        merge(result_split, result);
        exp(result, result);
    }

    int getSamples() const { return samples; }
    void setSamples(int val) { samples = val; }

    float getLambda() const { return lambda; }
    void setLambda(float val) { lambda = val; }

    bool getRandom() const { return random; }
    void setRandom(bool val) { random = val; }

    void write(FileStorage& fs) const
    {
        fs << "name" << name
           << "samples" << samples
           << "lambda" << lambda
           << "random" << static_cast<int>(random);
    }

    void read(const FileNode& fn)
    {
        FileNode n = fn["name"];
        CV_Assert(n.isString() && String(n) == name);
        samples = fn["samples"];
        lambda = fn["lambda"];
        int random_val = fn["random"];
        random = (random_val != 0);
    }

protected:
    String name;
    int samples;
    float lambda;
    bool random;
    Mat w;
};

Ptr<CalibrateDebevec> createCalibrateDebevec(int samples, float lambda, bool random)
{
    return makePtr<CalibrateDebevecImpl>(samples, lambda, random);
}

class CalibrateRobertsonImpl : public CalibrateRobertson
{
public:
    CalibrateRobertsonImpl(int _max_iter, float _threshold) :
        name("CalibrateRobertson"),
        max_iter(_max_iter),
        threshold(_threshold),
        weight(RobertsonWeights())
    {
    }

    void process(InputArrayOfArrays src, OutputArray dst, InputArray _times)
    {
        std::vector<Mat> images;
        src.getMatVector(images);
        Mat times = _times.getMat();

        CV_Assert(images.size() == times.total());
        checkImageDimensions(images);
        CV_Assert(images[0].depth() == CV_8U);

        int channels = images[0].channels();
        int CV_32FCC = CV_MAKETYPE(CV_32F, channels);

        dst.create(LDR_SIZE, 1, CV_32FCC);
        Mat response = dst.getMat();
        response = linearResponse(3) / (LDR_SIZE / 2.0f);

        Mat card = Mat::zeros(LDR_SIZE, 1, CV_32FCC);
        for(size_t i = 0; i < images.size(); i++) {
           uchar *ptr = images[i].ptr();
           for(size_t pos = 0; pos < images[i].total(); pos++) {
               for(int c = 0; c < channels; c++, ptr++) {
                   card.at<Vec3f>(*ptr)[c] += 1;
               }
           }
        }
        card = 1.0 / card;

        Ptr<MergeRobertson> merge = createMergeRobertson();
        for(int iter = 0; iter < max_iter; iter++) {

            radiance = Mat::zeros(images[0].size(), CV_32FCC);
            merge->process(images, radiance, times, response);

            Mat new_response = Mat::zeros(LDR_SIZE, 1, CV_32FC3);
            for(size_t i = 0; i < images.size(); i++) {
                uchar *ptr = images[i].ptr();
                float* rad_ptr = radiance.ptr<float>();
                for(size_t pos = 0; pos < images[i].total(); pos++) {
                    for(int c = 0; c < channels; c++, ptr++, rad_ptr++) {
                        new_response.at<Vec3f>(*ptr)[c] += times.at<float>((int)i) * *rad_ptr;
                    }
                }
            }
            new_response = new_response.mul(card);
            for(int c = 0; c < 3; c++) {
                float middle = new_response.at<Vec3f>(LDR_SIZE / 2)[c];
                for(int i = 0; i < LDR_SIZE; i++) {
                    new_response.at<Vec3f>(i)[c] /= middle;
                }
            }
            float diff = static_cast<float>(sum(sum(abs(new_response - response)))[0] / channels);
            new_response.copyTo(response);
            if(diff < threshold) {
                break;
            }
        }
    }

    int getMaxIter() const { return max_iter; }
    void setMaxIter(int val) { max_iter = val; }

    float getThreshold() const { return threshold; }
    void setThreshold(float val) { threshold = val; }

    Mat getRadiance() const { return radiance; }

    void write(FileStorage& fs) const
    {
        fs << "name" << name
           << "max_iter" << max_iter
           << "threshold" << threshold;
    }

    void read(const FileNode& fn)
    {
        FileNode n = fn["name"];
        CV_Assert(n.isString() && String(n) == name);
        max_iter = fn["max_iter"];
        threshold = fn["threshold"];
    }

protected:
    String name;
    int max_iter;
    float threshold;
    Mat weight, radiance;
};

Ptr<CalibrateRobertson> createCalibrateRobertson(int max_iter, float threshold)
{
    return makePtr<CalibrateRobertsonImpl>(max_iter, threshold);
}

}

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