Tagged Questions

0
votes
0answers
19 views

Read from Txt file and convert to float mat opencv

I need help with this. I am reading data from the text file. It has 3 column and 100 rows. The data is in (x,y,z) format. I want to combine x and y into one Mat data and Z into another one. For Z ...
2
votes
2answers
33 views

Creating NDWI Matrix in opencv

Firstly, if you don't know, i should tell what is ndwi. Ndwi stands for normalized difference water index. It is a graphical indicator for water and the value range is [-1 1]. Ndwi is defined as ...
0
votes
1answer
57 views

Matrix multiplication by it's transpose returning zeros matrix?

I'm multiplying a matrix by it's transpose and I'm getting a zeros matrix. I am multiplying other matrices and not having any problems. I've tried this both with cvMul and cvMulTransposed and always ...
1
vote
1answer
46 views

Method performance comparison

Which method is faster for retrieving a submat, adjustROI() or submat() ? I want to know it because im working with java and i got a loop over many images of size 1600*1200. Thanks in advance. P.S.: ...
0
votes
0answers
42 views

Increased processing time for every loop vector of Matrixes c++

This code gets called for multiple images in a row to create features of an image based on the Histogram of Orientated Gradients and a Correlogram. Problem is that with every image the processing time ...
1
vote
1answer
49 views

convert openCV matrix into vector

Looks deceptively easy. After all we know that an std or openCV vector can be easily converted into Matrix like this: vector<Point> iptvec(10); Mat iP(iptvec); The reverse is suggested in ...
3
votes
1answer
88 views

Correct spatial camera orientation

I'm performing a camera calibration as described in OpenCV calibration sample (which works fine for lens correction). Additionally I now want to do a spatial correction. Means when the camera is not ...
0
votes
1answer
202 views

OpenCV Mat per-element operation: vector-matrix multiplication

I is an mxn matrix and each element of I is a 1x3 vector (I is a 3-channel Mat image actually). M is a 3x3 matrix. J is an matrix having the same dimension as I and is computed as follows: each ...
1
vote
0answers
72 views

cvCalibrateCamera2 returns matrix with NaN-elements

I'm trying to do a camera calibration using cvCalibrateCamera2() but run into a strage problem: the returned intrinsic_matrix and distortion_coeffs contain invalid floats (=NaN). That's what I'm ...
1
vote
1answer
81 views

How do I access elements of a yml file in opencv?

I have a yml file which looks like this: %YAML:1.0 X: !!opencv-matrix rows: 13 cols: 40 dt: f data: [ 166.000000, 162.666667, 159.333333, 156.000000, 152.666667, 149.333333, ...
0
votes
1answer
95 views

Converting a large matrix into an image

hi so I've got a large 33 x 33 matrix in a text file. I've been working on an opencv project which basically reads the frames and calculates the similarities. So basically, I now have this large text ...
4
votes
2answers
63 views

Mat element bulk modification : negative to 0, positive to 1

I have a matrix of negative and positive integers. I want to set negative elements to 0 and positive elements to 1. I do not want to set each element individually. Is there any function/combination ...
0
votes
2answers
205 views

find homography matrix using openCV

i'm working on a project of image stitching using OpenCV 2.3.1 on Visual Studio 2012. For an unknown reason my programme don't work !! #include "opencv2/highgui/highgui.hpp" #include "opencv/cv.h" ...
0
votes
1answer
493 views

how to get Homography matrix using OpenCV (Stitching 2 images)

I'm working on OpenCV in visual studio 2012 , i tried to get Homography matrix to Stitch 2 images in opencv so really i don't know the steps to follow to do'it :
0
votes
1answer
71 views

what is equivalent with cvSVD in openCV for android

I can't find the method cvSVD in opencV 2.4.2 for android. can anyone help or give me some idea ?

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