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MKT-porter
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G2O(1) 基本例子 线性方程组

 

 

 

CMakeLists.txt

cmake_minimum_required(VERSION 3.1)
project(untitled2)

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_BUILD_TYPE Release)

set(ALL_TARGET_LIBRARIES "")


include(cmake/FindG2O.cmake)

#方式1
find_package(Eigen3 REQUIRED)
include_directories("/usr/local/include/eigen3")

#方式2 
#include(cmake/FindEigen3.cmake)


add_executable(fit_curve fit_curve.cpp)
target_link_libraries(fit_curve ${ALL_TARGET_LIBRARIES})

  

 

fit_curve.cpp

#include <Eigen/Core>
#include <iostream>

#include "g2o/stuff/sampler.h"
#include "g2o/core/sparse_optimizer.h"
#include "g2o/core/block_solver.h"
#include "g2o/core/optimization_algorithm_levenberg.h"
#include "g2o/core/base_vertex.h"
#include "g2o/core/base_unary_edge.h"
#include "g2o/solvers/dense/linear_solver_dense.h"
#include "g2o/core/robust_kernel_impl.h"

using namespace std;

/*!
 * 继承BaseVertex类,构造顶点
 */
class VertexParams : public g2o::BaseVertex<3, Eigen::Vector3d> {
public:
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW;

    VertexParams() = default;

    bool read(std::istream & /*is*/) override {
        cerr << __PRETTY_FUNCTION__ << " not implemented yet" << endl;
        return false;
    }

    bool write(std::ostream & /*os*/) const override {
        cerr << __PRETTY_FUNCTION__ << " not implemented yet" << endl;
        return false;
    }

    //该函数作用是更新顶点的估计值
    void setToOriginImpl() override {
        cerr << __PRETTY_FUNCTION__ << " not implemented yet" << endl;
    }

    //更新优化之后的顶点
    void oplusImpl(const double *update) override {
        Eigen::Vector3d::ConstMapType v(update);
        _estimate += v;
    }
};

/*!
 * 从BaseUnaryEdge继承得到一元边
 */
class EdgePointOnCurve : public g2o::BaseUnaryEdge<1, Eigen::Vector2d, VertexParams> {
public:
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW

    EdgePointOnCurve() = default;

    bool read(std::istream & /*is*/) override {
        cerr << __PRETTY_FUNCTION__ << " not implemented yet" << endl;
        return false;
    }

    bool write(std::ostream & /*os*/) const override {
        cerr << __PRETTY_FUNCTION__ << " not implemented yet" << endl;
        return false;
    }

    //边的误差计算
    void computeError() override {
        const VertexParams *params = dynamic_cast<const VertexParams *>(vertex(0));//顶点
        const double &a = params->estimate()(0);
        const double &b = params->estimate()(1);
        const double &lambda = params->estimate()(2);
        double fval = a * exp(-lambda * measurement()(0)) + b;
        _error(0) = std::abs(fval - measurement()(1));
    }
};

int main(int argc, char **argv) {
    int numPoints = 50;
    int maxIterations = 50;
    bool verbose = true;

    double a = 2.;
    double b = 0.4;
    double lambda = 0.2;
    Eigen::Vector2d *points = new Eigen::Vector2d[numPoints];
    ofstream points_file("../points.txt", ios::out);

    //准备用于拟合的数据
    for (int i = 0; i < numPoints; ++i) {
        double x = g2o::Sampler::uniformRand(0, 10);
        double y = a * exp(-lambda * x) + b;
        y += g2o::Sampler::gaussRand(0, 0.02);

        if (i == 20) {
            x = 8;
            y = 2.5;
        }

        points[i].x() = x;
        points[i].y() = y;
        points_file << x << " " << y << endl;
    }
    points_file.close();

    typedef g2o::BlockSolver<g2o::BlockSolverTraits<Eigen::Dynamic, Eigen::Dynamic> > MyBlockSolver;
    typedef g2o::LinearSolverDense<MyBlockSolver::PoseMatrixType> MyLinearSolver;

    g2o::SparseOptimizer optimizer;

    g2o::OptimizationAlgorithmLevenberg *solver = new g2o::OptimizationAlgorithmLevenberg(
            g2o::make_unique<MyBlockSolver>(g2o::make_unique<MyLinearSolver>()));

    optimizer.setAlgorithm(solver);

    VertexParams *params = new VertexParams();
    params->setId(0);
    params->setEstimate(Eigen::Vector3d(1, 1, 1));//初始化顶点的估计值
    optimizer.addVertex(params);

    for (int i = 0; i < numPoints; ++i) {
        EdgePointOnCurve *e = new EdgePointOnCurve;
        e->setInformation(Eigen::Matrix<double, 1, 1>::Identity());

        if (i == 20) {
            e->setInformation(Eigen::Matrix<double, 1, 1>::Identity() * 10);
        }

        e->setVertex(0, params);
        e->setMeasurement(points[i]);

        g2o::RobustKernelHuber *robust_kernel_huber = new g2o::RobustKernelHuber;
        robust_kernel_huber->setDelta(0.3);
        e->setRobustKernel(robust_kernel_huber);

        optimizer.addEdge(e);
    }

    optimizer.initializeOptimization();
    optimizer.setVerbose(verbose);
    optimizer.optimize(maxIterations);

    ofstream result_file("../result.txt");
    result_file << params->estimate()[0] << " "
                << params->estimate()[1] << " "
                << params->estimate()[2];
    result_file.close();


    cout << endl << "a, b, lambda: "
         << params->estimate()[0] << ", "
         << params->estimate()[1] << ", "
         << params->estimate()[2] << endl;

    delete[] points;

    return 0;
}

  

FindG2O.cmake

 

找到g2o

# Find the header files

find_path(G2O_INCLUDE_DIR g2o/core/base_vertex.h
        ${G2O_ROOT}/include
        $ENV{G2O_ROOT}/include
        $ENV{G2O_ROOT}
        /usr/local/include
        /usr/include
        /opt/local/include
        /sw/local/include
        /sw/include
        NO_DEFAULT_PATH
        )

# Macro to unify finding both the debug and release versions of the
# libraries; this is adapted from the OpenSceneGraph FIND_LIBRARY
# macro.

macro(FIND_G2O_LIBRARY MYLIBRARY MYLIBRARYNAME)

    find_library("${MYLIBRARY}_DEBUG"
            NAMES "g2o_${MYLIBRARYNAME}_d"
            PATHS
            ${G2O_ROOT}/lib/Debug
            ${G2O_ROOT}/lib
            $ENV{G2O_ROOT}/lib/Debug
            $ENV{G2O_ROOT}/lib
            NO_DEFAULT_PATH
            )

    find_library("${MYLIBRARY}_DEBUG"
            NAMES "g2o_${MYLIBRARYNAME}_d"
            PATHS
            ~/Library/Frameworks
            /Library/Frameworks
            /usr/local/lib
            /usr/local/lib64
            /usr/lib
            /usr/lib64
            /opt/local/lib
            /sw/local/lib
            /sw/lib
            )

    find_library(${MYLIBRARY}
            NAMES "g2o_${MYLIBRARYNAME}"
            PATHS
            ${G2O_ROOT}/lib/Release
            ${G2O_ROOT}/lib
            $ENV{G2O_ROOT}/lib/Release
            $ENV{G2O_ROOT}/lib
            NO_DEFAULT_PATH
            )

    find_library(${MYLIBRARY}
            NAMES "g2o_${MYLIBRARYNAME}"
            PATHS
            ~/Library/Frameworks
            /Library/Frameworks
            /usr/local/lib
            /usr/local/lib64
            /usr/lib
            /usr/lib64
            /opt/local/lib
            /sw/local/lib
            /sw/lib
            )

    if (NOT ${MYLIBRARY}_DEBUG)
        if (MYLIBRARY)
            set(${MYLIBRARY}_DEBUG ${MYLIBRARY})
        endif (MYLIBRARY)
    endif (NOT ${MYLIBRARY}_DEBUG)

endmacro(FIND_G2O_LIBRARY LIBRARY LIBRARYNAME)

# Find the core elements
FIND_G2O_LIBRARY(G2O_STUFF_LIBRARY stuff)
FIND_G2O_LIBRARY(G2O_CORE_LIBRARY core)

# Find the CLI library
FIND_G2O_LIBRARY(G2O_CLI_LIBRARY cli)

# Find the pluggable solvers
FIND_G2O_LIBRARY(G2O_SOLVER_CHOLMOD solver_cholmod)
FIND_G2O_LIBRARY(G2O_SOLVER_CSPARSE solver_csparse)
FIND_G2O_LIBRARY(G2O_SOLVER_CSPARSE_EXTENSION csparse_extension)
FIND_G2O_LIBRARY(G2O_SOLVER_DENSE solver_dense)
FIND_G2O_LIBRARY(G2O_SOLVER_PCG solver_pcg)
FIND_G2O_LIBRARY(G2O_SOLVER_SLAM2D_LINEAR solver_slam2d_linear)
FIND_G2O_LIBRARY(G2O_SOLVER_STRUCTURE_ONLY solver_structure_only)
FIND_G2O_LIBRARY(G2O_SOLVER_EIGEN solver_eigen)

# Find the predefined types
FIND_G2O_LIBRARY(G2O_TYPES_DATA types_data)
FIND_G2O_LIBRARY(G2O_TYPES_ICP types_icp)
FIND_G2O_LIBRARY(G2O_TYPES_SBA types_sba)
FIND_G2O_LIBRARY(G2O_TYPES_SCLAM2D types_sclam2d)
FIND_G2O_LIBRARY(G2O_TYPES_SIM3 types_sim3)
FIND_G2O_LIBRARY(G2O_TYPES_SLAM2D types_slam2d)
FIND_G2O_LIBRARY(G2O_TYPES_SLAM3D types_slam3d)

# G2O solvers declared found if we found at least one solver
set(G2O_SOLVERS_FOUND "NO")
if (G2O_SOLVER_CHOLMOD OR G2O_SOLVER_CSPARSE OR G2O_SOLVER_DENSE OR G2O_SOLVER_PCG OR G2O_SOLVER_SLAM2D_LINEAR OR G2O_SOLVER_STRUCTURE_ONLY OR G2O_SOLVER_EIGEN)
    set(G2O_SOLVERS_FOUND "YES")
endif (G2O_SOLVER_CHOLMOD OR G2O_SOLVER_CSPARSE OR G2O_SOLVER_DENSE OR G2O_SOLVER_PCG OR G2O_SOLVER_SLAM2D_LINEAR OR G2O_SOLVER_STRUCTURE_ONLY OR G2O_SOLVER_EIGEN)

# G2O itself declared found if we found the core libraries and at least one solver
set(G2O_FOUND "NO")
if (G2O_STUFF_LIBRARY AND G2O_CORE_LIBRARY AND G2O_INCLUDE_DIR AND G2O_SOLVERS_FOUND)
    set(G2O_FOUND "YES")
endif (G2O_STUFF_LIBRARY AND G2O_CORE_LIBRARY AND G2O_INCLUDE_DIR AND G2O_SOLVERS_FOUND)

include_directories(SYSTEM ${G2O_INCLUDE_DIR})
list(APPEND ALL_TARGET_LIBRARIES
        ${G2O_TYPES_DATA}
        ${G2O_CORE_LIBRARY}
        ${G2O_STUFF_LIBRARY}
        ${G2O_SOLVER_PCG}
        ${G2O_SOLVER_CSPARSE}
        ${G2O_SOLVER_CHOLMOD}
        ${G2O_TYPES_SLAM3D}
        ${G2O_TYPES_SLAM3D_ADDONS})

  

 

可视化代码

import numpy as np
import matplotlib.pyplot as plt

filename = './points.txt'
X, Y = [], []
with open(filename, 'r') as f:
    lines = f.readlines()
    for line in lines:
        value = [float(s) for s in line.split()]
        X.append(float(value[0]))
        Y.append(float(value[1]))

result_name = './result.txt'
with open(result_name, 'r') as r:
    lines = r.readlines()
    for line in lines:
        value = [float(s) for s in line.split()]
        a = float(value[0])
        b = float(value[1])
        my_lambda = float(value[2])

x = np.linspace(0, 10, 10)
y = a * np.exp(-my_lambda * x) + b

plt.plot(x, y, 'r')
plt.scatter(X, Y)
plt.show()

  

posted on 2024-07-18 22:05  MKT-porter  阅读(21)  评论(0)    收藏  举报
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