findHomography()を使用して2つの画像を比較しています。私はサーフとふるいにかけるアルゴリズムを使用すると、最新のAndroidのアーキテクチャ用にコンパイルするOpenCVの3.1.0にopencv_contribから余分なモジュールを追加しました。 ndk-build
を使用してライブラリを正常にコンパイルできます。imreadを使用して画像を読み取るときにエラーが発生するOpenCV
問題: 私はLG Nexus 5の上でアプリケーションを実行すると、私はimread
を使用して画像を読み取ることができていますが、私はLGネクサス5X、imread
上で同じアプリケーションを実行すると、画像を読み取れません。私はサムスンS6とOnePlus Xでテストして同じ問題があります。
#include <jni.h>
#include <string.h>
#include <stdio.h>
#include <android/log.h>
#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/xfeatures2d/nonfree.hpp"
#include "opencv2/opencv.hpp"
using namespace std;
using namespace cv;
#define LOG_TAG "nonfree_jni"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
jboolean detect_features(JNIEnv * env, jstring scenePath, jstring objectPath) {
const char *nativeScenePath = (env)->GetStringUTFChars(scenePath, NULL);
const char *nativeObjectPath = (env)->GetStringUTFChars(objectPath, NULL);
nativeScenePath = env->GetStringUTFChars(scenePath, 0);
nativeObjectPath = env->GetStringUTFChars(objectPath, 0);
(env)->ReleaseStringUTFChars(scenePath, nativeScenePath);
(env)->ReleaseStringUTFChars(objectPath, nativeObjectPath);
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Object path: ----- %s \n", nativeObjectPath);
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Scene path: ----- %s \n", nativeScenePath);
Mat img_object = imread(nativeObjectPath, CV_LOAD_IMAGE_GRAYSCALE);
Mat img_scene = imread(nativeScenePath, CV_LOAD_IMAGE_GRAYSCALE);
if(!img_object.data || !img_scene.data){
LOGI(" --(!) Error reading images ");
return false;
}
//-- Step 1: Detect the keypoints using SURF Detector
int minHessian = 400;
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Image comparison rows: ----- %d \n", img_object.rows);
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Image comparison colums: ----- %d \n", img_object.cols);
// cv::xfeatures2d::SurfFeatureDetector detector(minHessian);
Ptr<cv::xfeatures2d::SurfFeatureDetector> detector = cv::xfeatures2d::SurfFeatureDetector::create(minHessian);
std::vector<KeyPoint> keypoints_object, keypoints_scene;
detector->detect(img_object, keypoints_object);
detector->detect(img_scene, keypoints_scene);
//-- Step 2: Calculate descriptors (feature vectors)
// cv::xfeatures2d::SurfDescriptorExtractor extractor;
Ptr<cv::xfeatures2d::SurfDescriptorExtractor> extractor = cv::xfeatures2d::SurfDescriptorExtractor::create();
Mat descriptors_object, descriptors_scene;
extractor->compute(img_object, keypoints_object, descriptors_object);
extractor->compute(img_scene, keypoints_scene, descriptors_scene);
//-- Step 3: Matching descriptor vectors using FLANN matcher
FlannBasedMatcher matcher;
std::vector<DMatch> matches;
matcher.match(descriptors_object, descriptors_scene, matches);
double max_dist = 0; double min_dist = 100;
//-- Quick calculation of max and min distances between keypoints
for(int i = 0; i < descriptors_object.rows; i++)
{
double dist = matches[i].distance;
if (dist == 0) continue;
if(dist < min_dist) min_dist = dist;
if(dist > max_dist) max_dist = dist;
}
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "-- Max dist : %f \n", max_dist);
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "-- Min dist : %f \n", min_dist);
//-- Draw only "good" matches (i.e. whose distance is less than 3*min_dist)
std::vector<DMatch> good_matches;
for(int i = 0; i < descriptors_object.rows; i++)
{
if(matches[i].distance <= 0.1) //3*min_dist
{
good_matches.push_back(matches[i]);
}
}
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "FLANN total matches -----: %zu \n", matches.size());
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "FLANN good matches -----: %zu \n", good_matches.size());
Mat img_matches;
drawMatches(img_object, keypoints_object, img_scene, keypoints_scene,
good_matches, img_matches, Scalar::all(-1), Scalar::all(-1),
vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);
//-- Localize the object
std::vector<Point2f> obj;
std::vector<Point2f> scene;
for(int i = 0; i < good_matches.size(); i++)
{
//-- Get the keypoints from the good matches
obj.push_back(keypoints_object[ good_matches[i].queryIdx ].pt);
scene.push_back(keypoints_scene[ good_matches[i].trainIdx ].pt);
}
if (good_matches.size() >= 5)
{
Mat H = findHomography(obj, scene, CV_RANSAC);
//-- Get the corners from the image_1 (the object to be "detected")
std::vector<Point2f> obj_corners(4);
obj_corners[0] = cvPoint(0,0); obj_corners[1] = cvPoint(img_object.cols, 0);
obj_corners[2] = cvPoint(img_object.cols, img_object.rows); obj_corners[3] = cvPoint(0, img_object.rows);
std::vector<Point2f> scene_corners(4);
Mat output, matrix;
warpPerspective(img_object, output, H, { img_scene.cols, img_scene.rows });
////////////////////////////////////////////////////////////////////////////////
detector->detect(output, keypoints_object);
//-- Step 2: Calculate descriptors (feature vectors)
//cv::xfeatures2d::SurfDescriptorExtractor extractor;
Ptr<cv::xfeatures2d::SurfDescriptorExtractor> extractor = cv::xfeatures2d::SurfDescriptorExtractor::create();
extractor->compute(output, keypoints_object, descriptors_object);
extractor->compute(img_scene, keypoints_scene, descriptors_scene);
std::vector<std::vector<cv::DMatch>> matches2;
BFMatcher matcher;
matcher.knnMatch(descriptors_object, descriptors_scene, matches2, 2);
vector<cv::DMatch> good_matches2;
for (int i = 0; i < matches2.size(); ++i)
{
const float ratio = 0.8; // As in Lowe's paper; can be tuned
if (matches2[i][0].distance < ratio * matches2[i][1].distance)
{
good_matches2.push_back(matches2[i][0]);
}
}
if (matches2.size() == 0 || good_matches2.size() == 0) {
LOGI("End run!\n");
return false;
}
double ratioOfSimilarity = static_cast<double>(good_matches2.size())/static_cast<double>(matches2.size());
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Bruteforce total matches -----: %zu \n", matches2.size());
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Bruteforce good matches -----: %zu \n", good_matches2.size());
__android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, "Bruteforce similarity ratio -----: %f \n", ratioOfSimilarity);
if(ratioOfSimilarity >= 0.3) {
LOGI("End run!\n");
return true;
}
LOGI("End run!\n");
return false;
}
LOGI("End run!\n");
return false;
}
と、この行のメソッドブレーク:
if(!img_object.data || !img_scene.data){
LOGI(" --(!) Error reading images ");
return false;
}
イメージを読み取っていないテスト済みのデバイスには、アンドロイド6.0? – uelordi
@uelordiはいいくつかはアンドロイド6.0を持っていて、いくつかはアンドロイド7.0を持っています。しかし、アンドロイド6.0.1でnexus 5をテストしたところ、動作しています。 – Shahzeb
okです。したがって、実行時のアクセス権の問題ではありません。あなたは/ sdcardから画像を読んでいますか? apkの内部ストレージに? – uelordi