问 OpenCV错误:断言失败(a_size.width == len)

EN

背景

我目前正在尝试建立一个自主无人机使用ROS在我的Rapsberry Pi，这是运行一个Ubuntu伙伴16.04 LTS。解决目前识别红圈的计算机视觉问题。因为从本质上来说，无人机是不稳定的(因为有一个内部PID控制器稳定无人机)和由于照明条件，无人机经常检测到相同的圆，但非常不稳定的方式。为了解决这个问题，关于这个问题的评论建议我尝试视频稳定。

错误

这就是我目前所看到的错误：

OpenCV Error: Assertion failed (a_size.width == len) in gemm, file
/tmp/binarydeb/ros-kinetic-opencv3-3.1.0/modules/core/src/matmul.cpp,
line 900 terminate called after throwing an instance of
'cv::Exception'   what(): 
/tmp/binarydeb/ros-kinetic-opencv3-3.1.0/modules/core/src/matmul.cpp:900:
error: (-215) a_size.width == len in function gemm

代码

class Tracker {
    cv::Mat prevGray;
    vector<cv::Point2f> trackedFeatures;
    void processImage(const sensor_msgs::ImageConstPtr& msg) {
        // ROS declarations 
        cv_bridge::CvImagePtr cv_ptr;
        // Function Initializations
        if (freshStart == true) {
            cv::Mat rightTransform = cv::Mat::eye(3,3,CV_32FC1);
        cv::Mat gray; 
        cv::Mat copy_img;
        vector<cv::Point2f> corners;
        try { 
             cv_ptr = cv_bridge::toCvCopy(msg, 
                        sensor_msgs::image_encodings::BGR8);
        catch (cv_bridge::Exception& e) {
            ROS_INFO("cv_bridge exception");
            return;
        copy_img = cv_ptr->image;
        cv::cvtColor(cv_ptr->image, gray, cv::COLOR_BGR2GRAY);
        if (trackedFeatures.size() < 200) {
            cv::goodFeaturesToTrack(gray,corners,200,0.01,10);
            for (int i = 0; i < corners.size(); ++i) {
                trackedFeatures.push_back(corners[i]);
        if (!prevGray.empty()) {
            vector<uchar> status;
            vector<float> errors; 
            calcOpticalFlowPyrLK(prevGray, gray, trackedFeatures, corners,
                    status, errors, Size(10,10));
            if (countNonZero(status) < status.size() * 0.8) {
                cout << "cataclysmic error\n";
                rigidTransform = cv::Mat::eye(3,3,CV_32FC1);
                trackedFeatures.clear();
                prevGray.release();
                freshStart = true;
                return;
            } else {
                freshStart = false;
            cv::Mat_<float> newRigidTransform = estimateRigidTransform(
                    trackedFeatures, corners, false);
            cv::Mat_<float> nrt33 = cv::Mat_<float>::eye(3,3);
            newRigidTransform.copyTo(nrt33.rowRange(0,2));
            rigidTransform *= nrt33;
            trackedFeatures.clear();
            for (int i = 0; i < status.size(); ++i) {
                if (status[i]) {
                    trackedFeatures.push_back(corners[i]);
        // Debugging to see the tracked features as of now
        for (int i = 0; i < trackedFeatures.size(); ++i) {
            circle(cv_ptr->image, trackedFeatures[i], 3, Scalar(0,0,255), 
                CV_FILLED);
        imshow(OPENCV_WINDOW, cv_ptr->image); 
        cv::waitKey(3);
        gray.copyTo(prevGray);
};

现在我知道错误存在于语句 gray.copyTo(prevGray) 中。这是因为当我对此进行评论时，我没有发现任何错误。

方案的总体结构

class Tracker {
    // The ROS declarations 
    // Internal Declarations
    public:
    bool freshStart;
    Mat_<float> rigidTransform;
    Tracker():it_(nh1_) {
        image_sub_ = it_.subscribe("/ardrone/bottom/image_raw", 1,
                                        &Tracker::processImage, this);
        image_pub_ = it_.advertise("/stabImage", 1);
        cv::namedWindow(OPENCV_WINDOW);
    ~Tracker() {
        cv::destroyWindow(OPENCV_WINDOW);
    void processImage(const sensor_msgs::ImageConstPtr& msg) {
int main(int argc, char** argv)