calibrate_intrinsics.cc

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#include <iostream>
#include <string>
#include <cstdlib>
#include <stdexcept>
#include <climits>
#include "../lib/args.h"
#include "../lib/json.h"
#include "../lib/obj_img_correspondence.h"
#include "../lib/opencv.h"
#include "../lib/intrinsics.h"

using namespace tlz;


int main(int argc, const char* argv[]) {
    get_args(argc, argv, "obj_img_cors_set.json image_width image_height out_intrinsics.json [no_distortion]");
    std::string obj_img_cors_set_filename = in_filename_arg();
    int image_width = int_arg();
    int image_height = int_arg();
    std::string out_intrinsics_filename = out_filename_arg();
    bool no_distortion = bool_opt_arg("no_distortion");
    
    std::cout << "loading obj-img correspondences set" << std::endl;
    auto cors_set = decode_obj_img_correspondences_set<1, 1>(import_json_file(obj_img_cors_set_filename));
    
    std::cout << "preparing input data" << std::endl;
    std::vector<std::vector<cv::Vec3f>> object_points(cors_set.size());
    std::vector<std::vector<cv::Vec2f>> image_points(cors_set.size());
    for(int set_i = 0; set_i < cors_set.size(); ++set_i) {
        const auto& cors = cors_set[set_i];
        auto& obj_points = object_points[set_i];
        auto& img_points = image_points[set_i];
        for(const auto& cor : cors) {
            obj_points.push_back(cor.object_coordinates[0]);
            img_points.push_back(cor.image_coordinates[0]);
        }
    }
    
    cv::Size image_size(image_width, image_height);
    
    mat33 out_camera_mat;
    std::vector<real> out_distortion(5, 0.0);
    
    std::cout << "computing calibration" << std::endl;
    std::vector<cv::Mat> out_rotations, out_translations;
    const cv::TermCriteria term(cv::TermCriteria::COUNT | cv::TermCriteria::EPS, 50, DBL_EPSILON);
    int flags = CV_CALIB_ZERO_TANGENT_DIST;
    if(no_distortion) flags |= CV_CALIB_FIX_K1 | CV_CALIB_FIX_K2 | CV_CALIB_FIX_K3;
    real err = cv::calibrateCamera(
        object_points,
        image_points,
        image_size,
        out_camera_mat,
        out_distortion,
        out_rotations,
        out_translations,
        flags,
        term
    );
    std::cout << "reprojection error: " << err << std::endl;
    
    std::cout << "saving intrinsics" << std::endl;
    intrinsics intr;
    intr.K = out_camera_mat;
    intr.distortion.k1 = out_distortion[0];
    intr.distortion.k2 = out_distortion[1];
    intr.distortion.p1 = out_distortion[2];
    intr.distortion.p2 = out_distortion[3];
    intr.distortion.k3 = out_distortion[4];
    intr.width = image_width;
    intr.height = image_height;
    export_json_file(encode_intrinsics(intr), out_intrinsics_filename);
    
    std::cout << "done" << std::endl;
}