easy question but can't figure it out.
normaly its void minMaxLoc(InputArray src, double* minVal, double* maxVal=0, Point* minLoc=0, Point* maxLoc=0, InputArray mask=noArray())
But how does the mask looks like?
This is what i want: Its an one-dimensional Mat (only one row) and i want the minMax location of an interval(lower till upperBorder) of the Mat (maxRowGChnnl).
int lowerBorder,upperBorder;
lowerBorder = 30;
upperBorder = 100;
cv::minMaxLoc(maxRowGChnnl.row(0),&minValue,&maxValue,&minLoc,&maxLoc,(lowerBorder,upperBorder));
This is the maxRowGChnnl size:
maxRowGChnnl {flags=1124024325 dims=2 rows=1 ...} cv::Mat
flags 1124024325 int
dims 2 int
rows 1 int
cols 293 int
The code above abborts with:
OpenCV Error: Assertion failed ((cn == 1 && (mask.empty() || mask.type() == CV_8
U)) || (cn >= 1 && mask.empty() && !minIdx && !maxIdx)) in unknown function, fil
e ..\..\..\src\opencv\modules\core\src\stat.cpp, line 787
Thanks for your help.
mask should be cv::Mat the same size as axRowGChnnl.row(0) and type CV_8UC1. Enabled elements should have values equal 1 disabled 0.
You don't really need mask, but sub-matrix of maxRowGChnnl. You can do this by:
cv::minMaxLoc(maxRowGChnnl(Rect(lower,0,upper-lower,0)),&minValue,&maxValue,&minLoc,&maxLoc);
Related
Hi all I'm a rookie in C++ and Opencv as well. Kindly help me out on this.
I have a function (cv::aruco::estimatePoseSingleMarkers(markerCorners, markerLength, camMatrix, distCoeffs, rvecs,tvecs); that gives pose of the marker w.r.t camera.
I used a for loop to print out the values of tvecs from the function.
tvecs: [-0.0240248, 0.0161165, 0.052999]
When I print the size of tvecs it says the size is 1. But I think itś 1x3.
My requirement is to perform a matrix multiplication of the above mentioned tvces and a matrix of size [3x3].
How do I do this?
The following is the piece of code:
// Get frame and convert to OpenCV Mat
int openCVDataType=CV_8UC3;
cv::Mat image(cv::Size(pRequest->imageWidth.read(),pRequest->imageHeight.read()),openCVDataType,pRequest->imageData.read(),pRequest->imageLinePitch.read() );
//Undistort
cv::remap(image, imageUndist, map1, map2, CV_INTER_LINEAR);
//ArUco detection
cv::aruco::detectMarkers(imageUndist,dictionary,markerCorners,markerIds,detectorParams,rejectedCandidates);
if(markerIds.size() > 0) {
cv::aruco::estimatePoseSingleMarkers(markerCorners, markerLength, camMatrix, distCoeffs, rvecs,tvecs);
for(unsigned int d = 0;d<markerIds.size();d++) {
cout<<"tvecsss: "<<tvecs[d]<<endl;
cout<<"tvecs: "<<tvecs[d].t()<<endl;
cv::Mat rotMat;
cv::Rodrigues(rvecs[d],rotMat);
rotMat = rotMat.t();
cout<<"rotMat: "<<rotMat<<endl;
cout<<"translation: "<<-tvecs[d]*rotMat<<endl;
}
There's an error when I multiply tvecs[d]*rotMat. This the error:
mat.inl.hpp:1274: error: (-215:Assertion failed) data && dims <= 2 &&
(rows == 1 || cols == 1) && rows + cols - 1 == n && channels() == 1 in
function 'operator cv::Vec<_Tp, m>'
You need to change this:
-tvecs[d]*rotMat
into this:
rotMat*-tvecs[d]
Tvec is 3x1 matrix and rotMat is 3x3 matrix
I'm not familiar with opencv, but I need to use the function ‘remap’ to rectify the image.
I have an image with 960x1280, and a remap file called ‘remap.bin’ with 9.8MB（is equaled to 960x1280x4x2, which means the two floats in one position（x，y））；
Applies a generic geometrical transformation to an image.
C++: void remap(InputArray src, OutputArray dst, InputArray map1, InputArray map2, int interpolation, int borderMode=BORDER_CONSTANT, const Scalar& borderValue=Scalar())
map1 – The first map of either (x,y) points or just x values having the type CV_16SC2 , CV_32FC1 , or CV_32FC2 . See convertMaps() for details on converting a floating point representation to fixed-point for speed.
map2 – The second map of y values having the type CV_16UC1 , CV_32FC1 , or none (empty map if map1 is (x,y) points), respectively.
According to the explain，
I code like this：
int main(int argc, char* argv[]){
if(argc != 3){
printf("Please enter one path of image and one path of mapdata!\n");
return 0;
}
std::string image_path = argv[1];
char* remap_path = argv[2];
cv::Mat src = cv::imread(image_path);
cv::Mat dst;
dst.create( src.size(), src.type());
cv::Mat map2;
map2.create( src.size(), CV_32FC1);
map2.data = NULL;
cv::Mat mapXY;
mapXY.create( src.rows, src.cols, CV_64FC1);
FILE *fp;
fp = fopen(remap_path, "rb");
fread(mapXY.data, sizeof(float), mapXY.cols*mapXY.rows*2, fp);
fclose(fp);
imshow("src", src);
printf("remap!\n");
cv::remap(src, dst, mapXY, map2, cv::INTER_LINEAR);
imshow("dst", dst);
cv::waitKey(0);
return 0;
But when I run the program I get this error：
OpenCV Error: Assertion failed (((map1.type() == CV_32FC2 || map1.type() == CV_16SC2) && !map2.data) || (map1.type() == CV_32FC1 && map2.type() == CV_32FC1)) in remap, file /home/liliming/opencv-2.4.13/modules/imgproc/src/imgwarp.cpp, line 3262 terminate called after throwing an instance of 'cv::Exception' what(): /home/liliming/opencv-2.4.13/modules/imgproc/src/imgwarp.cpp:3262: error: (-215) ((map1.type() == CV_32FC2 || map1.type() == CV_16SC2) && !map2.data) || (map1.type() == CV_32FC1 && map2.type() == CV_32FC1) in function remap Aborted (core dumped)
I have no idea about it.
Could anyone help me？ or give some sample codes？
Thank you very much！
The documentation for OpenCV 3.1 says:
map1 The first map of either (x,y) points or just x values having the type
CV_16SC2 , CV_32FC1, or CV_32FC2.
The assert says that map1 doesn't have a type of CV_32FC2
This is because you are creating and reading it with a type of CV_64FC1.
You need to convert it to the correct type: array of two dimensions of type CV_32FC2 (two 32-bit floats per element.)
The documentation goes on to say:
See `convertMaps` for details on converting a
floating point representation to fixed-point for speed.
Documentation can be found here: https://docs.opencv.org/3.1.0/da/d54/group__imgproc__transform.html#gab75ef31ce5cdfb5c44b6da5f3b908ea4
I separate the remap table into two tables remapX， remapY.
Like this:
float *data_xy = (float *)malloc(sizeof(float)*960*1280*2);
FILE *fp;
fp = fopen(remap_path, "rb");
fread(data_xy, sizeof(float), 960*1280*2, fp);
fclose(fp);
for(int y=0; y<1280; ++y){
for(int x=0; x<960; ++x){
map_x.at<float>(y, x) = data_xy[(y*960+x)*2];
map_y.at<float>(y, x) = data_xy[(y*960+x)*2+1];
}
}
And then use the
cv::remap(src, dst, map_x, map_y, cv::INTER_LINEAR);
It works well.
But I don't know how to use one parameter map1 to finish remap.
So I am having basically the same issue described in this post from last year, and am not getting anywhere with solving it. I am calling calibrateCamera and am getting the error "Assertion failed (nimages > 0 && nimages == (int) imagePoints1.total() && (!imgPtMat2 || nimages == (int)imagePoints2.total()) in cv::collectCalibrationData".
The line of code that is getting this error is:
double rms = calibrateCamera(objectPoints, imagePoints, imageSize, cameraMatrix,
distCoeffs, rvecs, tvecs, s.flag | CALIB_FIX_K4 | CALIB_FIX_K5);
I have checked the size of both objectPoints and imagePoints, and they are the same, as shown in the images below.
Both imagePoints and objectPoints contain points that make sense-- they are not filled with incorrect values or empty. I took a look at the collectCalibrationData code because that was where the assertion was failing, and it seems my problem is that the function itself seems to calculate the size of each vector incorrectly, or at least in a way that does not give a consistent size. Code for relevant part of function collectcalibrationData shown below:
static void collectCalibrationData( InputArrayOfArrays objectPoints,
InputArrayOfArrays imagePoints1,
InputArrayOfArrays imagePoints2,
Mat& objPtMat, Mat& imgPtMat1, Mat* imgPtMat2,
Mat& npoints )
{
int nimages = (int)objectPoints.total();
int i, j = 0, ni = 0, total = 0;
CV_Assert(nimages > 0 && nimages == (int)imagePoints1.total() &&
(!imgPtMat2 || nimages == (int)imagePoints2.total()));
for( i = 0; i < nimages; i++ )
{
ni = objectPoints.getMat(i).checkVector(3, CV_32F);
if( ni <= 0 )
CV_Error(CV_StsUnsupportedFormat, "objectPoints should contain vector of vectors of points of type Point3f");
int ni1 = imagePoints1.getMat(i).checkVector(2, CV_32F);
if( ni1 <= 0 )
CV_Error(CV_StsUnsupportedFormat, "imagePoints1 should contain vector of vectors of points of type Point2f");
CV_Assert( ni == ni1 );
total += ni;
}
It seems that the size of each of the vectors is calculated with nimages = (int)objectPoints.total() and nimages == (int)imagePoints.total(). I print out the values these produce with these two lines (converting the vectors to InputArrayofArrays b/c that's what collectCalibrationData does):
cv::InputArrayOfArrays IMGPOINT = imagePoints; std::cout << (int) IMGPOINT.total() << std::endl;
cv::InputArrayOfArrays OBJPOINT = objectPoints; std::cout << (int) OBJPOINT.total() << std::endl;
These statements produce a seemingly random integer every time I run the program-- they are not consistent and are never equal to each other. At this point, I'm stuck. I'm not sure why collectCalibrationData is getting the wrong values for the size of my vectors, and why converting the vectors to an InputArrayofArrays seems to change their size. Any tips? I've seen this problem asked once or twice before but there's never been an answer.
I am using VS 2013 and OpenCV 3.0.0.
I'm trying to learn OpenCV (Using version 3.0.0).
Right now I'm trying to see what the point operatioins do to various images, everything is going fine until I tried to do the magnitude operation, which requires inputs be in the form of
magnitude(InputArray x, InputArray y, OutputArray magnitude)
It also describes that x and y should be floating-point arrays of x/y-coordinates of the vectors and also the same size.
I've tried making a Vector of Mat's and splitting up the input image into these vectors and then doing the magnitude operator on them, but this didn't work. So I think I need to pass the arguments as columns and rows, but now I'm getting the error
OpenCV Error: Assertion failed (src1.size() == src2.size() && type == src2.type() && (depth == CV_32F || depth == CV_64F)) in magnitude, file /home/<user>/opencv-3.0.0-beta/modules/core/src/mathfuncs.cpp, line 521
terminate called after throwing an instance of 'cv::Exception'
what(): /home/<user>/opencv-3.0.0-beta/modules/core/src/mathfuncs.cpp:521: error: (-215) src1.size() == src2.size() && type == src2.type() && (depth == CV_32F || depth == CV_64F) in function magnitude
Aborted (core dumped)
And I'm not sure why, because I am clearly converting the input Mats to CV_64F types.
Am I using the magnitude function wrong? Or just passing it the wrong data?
void Magnitude(Mat img, Mat out)
{
img.convertTo(img, CV_64F);
out.convertTo(out, CV_64F);
for(int i = 0 ; i < img.rows ; i ++)
for(int j = 0 ; j < img.cols ; j++)
cv::magnitude(img.row(i), img.col(j), out.at<cv::Vec2f>(i,j));
cv::normalize(out,out,0,255,cv::NORM_MINMAX);
cv::convertScaleAbs(out,out);
cv::imshow("Magnitude", out);
waitKey();
}
void magnitude(InputArray x, InputArray y, OutputArray magnitude)
where x, y and magnitude must have the same size. In your case it means that your image have to be quadratic. Is it right?
A sample usage:
cv::Sobel(img, gx, img.depth(), 1, 0, 3);
cv::Sobel(img, gy, img.depth(), 0, 1, 3);
cv::Mat mag(gx.size(), gx.type());
cv::magnitude(gx, gy, mag);
HI i found this code to compare images
cv::Mat img1 = ...
cv::Mat img2 = ...
cv::Mat result = ...
int threshold = (double)(img1.rows * img1.cols) * 0.7;
cv::compare(img1 , img2 , result , cv::CMP_EQ );
int similarPixels = countNonZero(result);
if ( similarPixels > threshold ) {
cout << "similar" << endl;
}
but since i m new to OPENCV i dont know what are the values for " cv::Mat img1=..."
please help me out and tried out the code with the image path as value but its giving an error
void compare(const MatND& src1, const MatND& src2, MatND& dst, int cmpop)
compare function takes 4 parametres and this are ;
•src1 – The first source array
•src2 – The second source array; must have the same size and same type as src1
•value – The scalar value to compare each array element with
•dst – The destination array; will have the same size as src1 and type= CV_8UC1
And as i understand this image has some fiducial points like coordinate system ( X / Y )
such as ;
1 45 123
2 56 164
3 64 147
and with these points are storing in array and then it send arrays to compare function in order to find matchers .
If you want to work with image comparasion my advise is you can search feret database which is free to use for research.
You can use imread to load an image to cv::Mat img1, e.g.
cv::Mat img1 = imread("c:\\test.bmp"); // To load an RGB image