Android JNI编程 调用c语言卡尔曼滤波。。。

1、kalman.cpp

 

//
// Created by xy on 2021/6/12.
//

#include "kalman.h"

float Q = Q_DEFAULT;
float R = R_DEFAULT;

float x_last, p_last;

void ResetValue(){
    x_last = 0;
    p_last = 0;
}

void ProcessQset(float q){
    Q = q;
}

void ProcessRset(float r){
    R = r;
}

float KalmanFilter(float ResrcData)
{
//    static float x_last;
//    static float p_last;

    float x_mid;
    float x_now;

    x_mid = x_last;

    float p_mid;
    float p_now;
    float kg;

    //x_last=x(k-1|k-1),x_mid=x(k|k-1)
    x_mid = x_last;
    //p_mid=p(k|k-1),p_last=p(k-1|k-1),Q=噪声
    p_mid = p_last + Q;
    //kg为kalman filter，R为噪声
    kg = p_mid / (p_mid + R);
    //估计出的最优值
    x_now = x_mid + kg * (ResrcData - x_mid);
    //最优值对应的covariance
    p_now = (1 - kg) * p_mid;
    //更新covariance值
    p_last = p_now;
    //更新系统状态值
    x_last = x_now;

    return x_now;
}

 

 

2、kalman.h

 

//
// Created by xy on 2021/6/12.
//

#ifndef PHMETER_KALMAN_H
#define PHMETER_KALMAN_H

#include "../common.h"

/**
 * Q: ProcessNiose_Q
 * R: MeasureNoise_R
 * Q:过程噪声，Q增大，动态响应变快，收敛稳定性变坏
 * R:测量噪声，R增大，动态响应变慢，收敛稳定性变好
 */
#define Q_DEFAULT 0.01
#define R_DEFAULT 10

/**
 * 重置记录值
 */
void ResetValue();

/**
 * 设置滤波参数Q
 * @param q
 */
void ProcessQset(float q);

/**
 * 设置滤波参数R
 * @param r
 */
void ProcessRset(float r);

/**
 * 卡尔曼滤波C语言实现
 * @param ResrcData 输入
 * @return float    返回：滤波后数据
 */
float KalmanFilter(float ResrcData);

#endif //PHMETER_KALMAN_H

 

 

3、common.h

 

//
// Created by xy on 2021/6/12.
//

#ifndef PHMETER_COMMON_H
#define PHMETER_COMMON_H

#include <jni.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <Android/log.h>
#include <Android/asset_manager.h>
#include <Android/asset_manager_jni.h>

#define TAG "api.linkzill.jni"

#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG ,__VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG ,__VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,TAG ,__VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG ,__VA_ARGS__)
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,TAG ,__VA_ARGS__)


#endif //PHMETER_COMMON_H

 

 

4、filter-lib.cpp

 

//
// Created by Think on 2021/6/11.
//
#include "common.h"
#include "filter/kalman.h"
#include <iostream>

extern "C" {

    JNIEXPORT void Java_api_linkzill_jni_FilterApiJNI_resetVal(JNIEnv *env){
        ResetValue();
    }

    JNIEXPORT void Java_api_linkzill_jni_FilterApiJNI_setQ(JNIEnv *env, jfloat q){
        ProcessQset(q);
    }

    JNIEXPORT void Java_api_linkzill_jni_FilterApiJNI_setR(JNIEnv *env, jfloat r){
        ProcessRset(r);
    }

    JNIEXPORT jfloat JNICALL Java_api_linkzill_jni_FilterApiJNI_kalmanFilter(JNIEnv *env, jfloat val){
        return KalmanFilter(val);
    }

}

 

 

5、FilterApiJNI

 

package api.linkzill.jni;

/**
 * Author:Think
 * Time:2021/6/11 17:11
 * Description:This is FilterApiJNI
 */
public class FilterApiJNI {

    static {
        // 加载。名字和。CMakeLists.txt  的名字一样
        System.loadLibrary("filter-lib");
    }

    public static native void resetVal();

    public static native void setQ(float q);

    public static native void setR(float r);

    public static native float kalmanFilter(float val);

}

 

 

 

6、CMakeLists.txt

 

#指定CMake构建本地库时所需的最小版本
cmake_minimum_required(VERSION 3.4.1)

# 输出路径
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/src/main/jni/${ANDROID_ABI})

# 配置加载native依赖
include_directories(${CMAKE_SOURCE_DIR}/src/main/cpp/)

set(CMAKE_VERBOSE_MAKEFILE on)

#native-lib
#file(GLOB_RECURSE CPP_SRCS "src/main/cpp/*.cpp")
set(GLOB_RECURSE_DIR ${CMAKE_SOURCE_DIR}/src/main/cpp)

add_library( filter-lib SHARED
                ${GLOB_RECURSE_DIR}/filter-lib.cpp
                ${GLOB_RECURSE_DIR}/filter/kalman.cpp)

find_library( # Sets the name of the path variable.
        log-lib

        # Specifies the name of the NDK library that
        # you want CMake to locate.
        log )

target_link_libraries( # Specifies the target library.

        filter-lib

        # Links the target library to the log library
        # included in the NDK.
        ${log-lib} )

 

 

 

7、build.gradle配置

 

    defaultConfig {
        minSdkVersion ext.android.minSdk
        targetSdkVersion ext.android.targetSdk
        versionCode project.ext.versionCode //版本号
        versionName ext.android.versionName //版本名
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

        // 增加cmake控制属性
        externalNativeBuild {
            cmake {
                // 指定编译架构 可省略
                abiFilters 'arm64-v8a', 'armeabi-v7a', 'x86', 'x86_64'
                // cpp 编译时的额外选项 可省略
                cppFlags ""
            }
        }
    }

    // 指定CMakeLists.txt路径
    externalNativeBuild {
        cmake {
            // 在该文件种设置所要编写的c源码位置，以及编译后so文件的名字
            path "CMakeLists.txt"
            // cmake版本 可以省略
            version "3.10.2"
        }
    }

 

 

 

8、整体目录结构