OpenCV (Open Source Computer Vision) is a cross-platform library of programming functions for real time computer vision.

learn more… | top users | synonyms

0
votes
0answers
23 views

what are moments?

Hello all I'm using opencv after using findcontours I apply moments here is the vague wiki definition - http://en.wikipedia.org/wiki/Image_moment Can someone please explain in simpler words - ...
0
votes
1answer
37 views

Is this image good enough for OCR?

Hello I'm trying to ocr on a special image. I've done adaptive threshold , polartocartesian transformation. this is my original image this is adaptive threshold this is polartocartesian ...
1
vote
0answers
15 views

Gap Filling Contours / Lines

I have the following image: and I would like to fill in its contours (i.e. I would like to gap fill the lines in this image). I have tried a morphological closing, but using a rectangular kernel ...
0
votes
1answer
15 views

How to choose suitable segmentation process for image processing

Hello I'm new on image processing. I know there are a lot of threshold and region growing algorithms to use. But I would like to know what is the trick for choosing suitable method for an image ? ...
4
votes
2answers
125 views

How to remove the noise without destroying the main edge?

I am working on a project. I want to segment a logo from a car and the picture's size is 3648*2432. The logo is selected by the red rectangle. I extracted this area and turn into gray level. The ...
3
votes
1answer
106 views

Is it possible to hack camera calibration without having access to the camera?

Many times we have a stream of video to process without access to camera. Having access to camera matrix would be beneficial for various processing techniques. Is it possible to hack camera ...
0
votes
0answers
20 views

opencv4Android,How to draw good matches?

I am doing a project on panoramic stitching of Images using openCV4Ansroid and I want to use features2d to draw good matches ...
4
votes
1answer
59 views

Feature Detection on a Circular Metal Surface for Character Recognition

Hello I'm trying to recognize characters on the circular metal surface. Without any preprocessing I could match cropped features with original image. I've actually cropped 2 characters together to ...
0
votes
1answer
66 views

OpenCV Motion Analysis: Optical Flow vs Motion History

OpenCV Motion Analysis Documentation lists multiple techniques for motion tracking: Sparse Optical Flow | calcOpticalFlowPyrLK, Dense Optical Flow | calcOpticalFlowFarneback, and Motion History ...
0
votes
0answers
24 views

How to choose extrinsic parameters when projecting 3d points to 2d points?

I want to use voxel carving to realize the reconstruction of a target. Three cameras placed at orthogonal places as follows: One important step is that I have to back project 3d points to 2d points ...
0
votes
1answer
61 views

How to detect the exception by SVM with openCV

I have implemented SVM by openCV. However, I have a problem about SVM with openCV. For example, I have six categories, but I just use "five" of them to train my SVM. When testing, I want my system ...
0
votes
0answers
47 views

Why Normalized Cross Correlation Score of different templates is high?

I am using OpenCv's built in template matching function to search for an object in image. I am using Normalized Cross Correlation Method.The function is returning a value which I think indication of ...
0
votes
1answer
39 views

Shape recognition, hough transform

I'm trying to match a picture saying "this is ducks, this is towers" by giving votes from the hough transform of a picture. I've found this article ...
1
vote
1answer
24 views

Does accurate translation estimation using a camera matrix mean the orientation estimation will also be accurate?

Pose Estimation of single camera and planar pattern: If I have an appropriate camera matrix with intrinsic parameters that allows me to calculate translation of the camera relative to a chessboard, ...
1
vote
1answer
139 views

Detecting text lines in image by means of Hough Transform

In my Android App,I have to detect text lines in images.I want to use Hough Transform to detect lines.You can see an image below: I got edges in image by ...
0
votes
0answers
54 views

Image processing: Importance of phase

I was doing some experiment on image processing. I wanted to explore the importance of phase and Magnitude. I followed the following approach: Take 2 image of same dimension. Apply Fourier ...
0
votes
0answers
33 views

Best segmentation method

This is part of my samples ...
0
votes
1answer
76 views

Skeleton from distance map

Can anyone give some tips how to obtain Skeleton from distance map? I already managed to obtain skeleton using erased method (e.g. zhang suen) but it's time consuming because it's an iterative method ...
0
votes
2answers
280 views

Finding local brightness maximas with OpenCV

I want to find points (of a processed image) that are the brightest in their local region. Basically, I want all of the points whose 8 neighbors are all smaller but I want to have brighter maxima ...
0
votes
1answer
50 views

Is a change in colorspace needed when comparing colors only evaluated by the computer?

I am confused about the need to change color space for color comparison. I have read about delta E, the Lab format, and I do understand that comparisons in the RGB color space will not seem ...
2
votes
0answers
115 views

Why is LBP generaly faster than HAAR?

I am digging into Haar like and LBP features. More precisely its implementation in OpenCV. Every article or forum entry I found states, that LBP is faster than Haar. My local tests also confirm this ...
0
votes
2answers
178 views

Template matching or object recognition?

Problem: I have a photo of an object (a manufactured part like the attached photo below), using my Andoird phone camera I want to verify if the object in camera preview matches to the template or not. ...
0
votes
0answers
45 views

Problem in openCV casade classifier

I am trying to train cascade classifier using "opencv_traincascade" utility. I'm having 100 positive images and 500 negative images. I have created .vec file using following command: ...
1
vote
0answers
25 views

High triangulation error

I have implemented a 2D->3D point triangulation method, which uses 2 poses P1 and P2 and 2 points back-projected to z=1 point1 and point2 to recover depth: ...
0
votes
0answers
43 views

State of the art post processing techniques for segmented images

I've been working on grabcut-based approaches to human segmentation in images. I've combined colour, motion and face detection cues to provide some seeds and perform a grabcut. While the results have ...
1
vote
0answers
95 views

Visual regression test - Extract elements of GUI-Screenshot - MSER OpenCV

For a visual regression test I need to compare screenshots of webpages (different release-versions). I started with pixel by pixel compare. Actually I split the screenshot in different parts (maybe ...
0
votes
1answer
97 views

Using ROC curves for comparing the performance of SIFT and SURF

I want to compare the performance of SIFT and SURF against some standard image set. After a bit of research, I found that ROC curves are one of the best ways to do this task. In order to plot ROC ...
2
votes
1answer
410 views

Zernike Moments' implementation in OpenCV

The reason why Hu moments were implemented in OpenCV and why Zernike moments were not implemented is looking like their performance similar as stated in this paper. As stated in the paper Zernike ...
1
vote
0answers
250 views

MPEG-7 descriptors' implementation in OpenCV

I'm looking for implementation of MPEG-7 descriptors which are compatible with OpenCV's recent versions and containing "region-based shape descriptor ART(Angular Radial Transformation)". I ...
1
vote
2answers
108 views

Grayscale conversion before applying sobel gradient operator

I am currently replacing a hand-made image processing library by OpenCV. The programmer who worked on this library had implemented the sobel gradient function. This implementation is right except that ...
0
votes
1answer
123 views

MATLAB rand and C++ rand() [closed]

I am trying to port a MATLAB code into C++ and found the usage of rand in MATLAB. Is MATLAB's rand function and C++ ...
0
votes
0answers
41 views

OpenCV: Is NormalBayesClassifier::train function running ok?

I am have the code from here. I have changed the images with some of my own and I have seen that SVM is not working. That is not a problem because I have found on ...
-1
votes
2answers
67 views

How to proceess Image with curved corners and edges to give sharp Corners?

I have several Images of shape H, F, I, L.. which have curved corners. How do I process them to give sharp right-angled corners? I tried approximating them with inner rectangles, but this takes a LOT ...
5
votes
3answers
533 views

Is it possible to convert from 2D to 3D form?

I have captured car positions at different frames from the video. Suppose car's(e.g.left side car which is coming towards us in the images) centroid at video frame1 is P(x1,y1) and Q(x2,y2) at video ...
0
votes
1answer
49 views

Detecting blobs that connects to any other blob, maybe with OpenCV

In the image, I connects to universe, but II and III not. I need to detect both II and III, also I if possible. Is it possible with current computer vision libraries?
0
votes
0answers
111 views

how to retreive descriptors from BoW dictionary and match it with query image descriptor - CBIR?

I am trying to implement Content based Image retrieval using BoW-SIFT-SVM. I succesfully created BoW codebook. In the retrieval phase how to match the query descriptor with the dictionary? i.e., how ...
0
votes
2answers
134 views

how to make image editing filters

I am trying to make filters for days but now I just want to know the experience of others rather than go on to wrong way and finally decided to put my query over ...
1
vote
1answer
333 views

OpenCV Haar Classifier - best type of positive images

I'm currently collating images to try and develop a HAAR classifier using the OpenCV traincascade functionality. The objects I want to detect are small and numerous (bees), and I'm curious as to ...
0
votes
0answers
224 views

How to make color balance of photoshop using opencv

I want to make the same thing programmatically like Color balance in Photoshop , like in below image if we have same bar ...
1
vote
3answers
146 views

Trying to translate formula for blending mode

I am using OpenCV C++ for making the blending mode like in photoshop, I want to make overlay mode in it. I search its alternate in OpenCV in which I found this ...
0
votes
1answer
102 views

How vibrance method of photoshop work in opencv

Can somebody please explain how Photoshop vibrance function can use in opencv c++ ? so that I may reproduce the same effects in my application. Here is the vibrance ...
0
votes
1answer
165 views

Counting human movement of exercise using ROI or pre-set passing line with OpenCV

I'm currently doing my final year Degree in computing studies. The project I'm working on is a video of a webcam or computer webcam to have 2 pre-defined ROI (Region of Interest) on top and bottom ...
0
votes
0answers
24 views

Where can I find annotated databases of faces with profile views?

I'm working on a project that uses AAMs (Active Appearance Models). I'd like to have an AAM with profile view. Is is possible to get free annotated images of faces in a profile view?
0
votes
1answer
290 views

Histogram and binary image in opencv? [closed]

I would like to compute how many zeros and ones (e.i. 255) in a binary image. The following code to generate a binary image by using Matlab. ...
0
votes
0answers
69 views

reducing chroma of image on client and reconstructing on server

I have a C# desktop application. I am using Emgu wrapper to openCV. My objective is to upload images in the most efficient way I can. I have hit upon the idea of loading an image (jpeg) into memory ...
0
votes
0answers
526 views

Sharpening an image using emgu

I have c# desktop application and I am using emgu framework as a wrapper for OpenCV. I am trying to sharpen an image because the input images are not great. I tired a technique I found via searches ...
0
votes
1answer
125 views

How to make filters?

I am trying to make filters like sepia filter in my app like other photo editing applications , till now I don't have any idea about it , Can any one help me out ...
1
vote
2answers
708 views

Improve contrast when image has a flood of white balancing

I have an image taken a night time. I apply _EqualizeHist to it. But the result is a high level of whiteness running through the image. This is the image: I had asked this question in a slightly ...
1
vote
0answers
171 views

Motion and Distortion Estimation using multiple still images?

TL/DR: I'd like to take the median of lots of images to make a single "better" image. The problem is, the camera is slowly moving, and there is significant lens distortion. On the plus side the ...
4
votes
1answer
222 views

Corner detection using Chris Harris & Mike Stephens [duplicate]

I am not able to understand the formula, What is $W$ (window) and intensity in the formula mean, I found this formula in opencv doc ...