regulizedFineTuneKaessCorners.m

%{
 * Copyright (C) 2013-2020, The Regents of The University of Michigan.
 * All rights reserved.
 * This software was developed in the Biped Lab (https://www.biped.solutions/) 
 * under the direction of Jessy Grizzle, grizzle@umich.edu. This software may 
 * be available under alternative licensing terms; contact the address above.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice, this
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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 * AUTHOR: Bruce JK Huang (bjhuang[at]umich.edu)
 * WEBSITE: https://www.brucerobot.com/
%}

function X = regulizedFineTuneKaessCorners(X, Y, edges_points, P, correspondance_per_pose, display)
    theta_x = optimvar('theta_x', 1, 1,'LowerBound',-5,'UpperBound',5); % 1x1
    theta_y = optimvar('theta_y', 1, 1,'LowerBound',-5,'UpperBound',5); % 1x1
    theta_z = optimvar('theta_z', 1, 1,'LowerBound',-5,'UpperBound',5); % 1x1
    T = optimvar('T', 1, 3,'LowerBound',-0.1,'UpperBound',0.1);

    prob = optimproblem;
    num_scan = size(X, 2)/correspondance_per_pose; % 4 correspondance per scan
    for i = 1 : num_scan
        scan_num = correspondance_per_pose * (i-1) + 1;
        f = fcn2optimexpr(@regulizedCostOfFineTuneKaessCorners, ...
                          theta_x, theta_y, theta_z, T, ...
                          X(:,scan_num:scan_num+correspondance_per_pose-1), ...
                          Y(:,scan_num:scan_num+correspondance_per_pose-1), edges_points(i), P);

        prob.Objective = f;

        x0.theta_x = 0;
        x0.theta_y = 0;
        x0.theta_z = 0;
        x0.T = [0 0 0];
        options = optimoptions('fmincon', 'MaxIter',5e2, 'Display','off', 'TolX', 1e-12, 'FunctionTolerance', 1e-8, 'MaxFunctionEvaluations', 3e4, 'StepTolerance', 1e-20);
 
        [sol, fval, ~, ~] = solve(prob, x0, 'Options', options);
        R_final = rotx(sol.theta_x) * roty(sol.theta_y) * rotz(sol.theta_z);
        H_fine_tune = eye(4);
        H_fine_tune(1:3, 1:3) = R_final;
        H_fine_tune(1:3, 4) = sol.T';
        if display
            disp('Kaess new H_LT: ')
            disp(H_fine_tune)
        end

        X(:,scan_num:scan_num+correspondance_per_pose-1) = H_fine_tune * X(:,scan_num:scan_num+correspondance_per_pose-1);
    end
end