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2013-11-07 14:03:39 -0600 | asked a question | How to establish data base for object detection? I want to set up an object detection based on camera images. The idea is that I start with an empty database and subsequently add objects into it with the camera. So far I have a tracking algorithm (https://code.google.com/p/opencv-cookbook/source/browse/trunk/Chapter%2010/featuretracker.h?r=2) (modified but basically the same). What I am now not sure about is, how to set up the database. The idea is the following: I am detecting SIFT feature points (lets say frame1 1000 FeaturePoints(FPs)) in the first frame. In the subsequent frame2 I am taking over the features I recognized in frame1 due to the tracking algorithm (say 500). With this 500 I go to frame3 and take over those FPs I can track from frame2 (say 400) and so on. This means that the number of feature points in constantly dropping over the frames. Similar to the Algorithm I want to introduce two thresholds of say 100FPs and 40FPs. If I undergo 100Fps (assume this happens in frame6) - then I start to detect again SIFT features in frame6 and push the points with that back to 1000. Unless the drop is so high that I do not only undergo 100 FPs but also 40FPs in frame6 then I consider this frame to show a new Object. Let's say I have to refresh my FPs every 6 frames and after 7 refreshs I drop below 40 and want to classify the object. This means I have recognized 7000 Fps for Object 1. But many of them are very similar or even the same. Therefore I thought about putting this FPs into an SVM to learn the object. Now the question is what kind of SVM is the best for my purpose. I cannot do a "negative training", means I have no images which are showing the wrong object to train the classifier. I could do that once I have detected a few objects. Additionally I want to save my results on the hard disk so that I can load them and proceed another time learning/matching other objects. I hope my problem became clear and somebody can give me inspiration or good advice how to proceed. Best Regards |
2013-11-07 11:04:19 -0600 | asked a question | Feature tracking - calcOpticalFlowPyrLK?? Hello, I use the following feature tracker: https://code.google.com/p/opencv-cookbook/source/browse/trunk/Chapter%2010/featuretracker.h?r=2 What I do not understand is how it works with the in-/output point positions in the images. If there is no prev. Image, the algorithm stores the current image (gray) in (gray_prev) and then calls In the first iteration gray_prev and gray are the same and therefore all points in points[0] can be copied to points[1] - fine. Then the algrithm kicks out some points in points[1] and swaps gray_prev and gray respectively points[1] and points[0]. Which means that in the next iteration - right after calling the processing method, the keypoints in points[0] correspond to the previus frame ( gray_prev ). Now, if the number of points in points[0] is to low, new keypoints - which were found in the current image (gray) - are added This means that we mix keypoints from both images in points[0]?! How does this work? |
2013-10-22 13:46:37 -0600 | commented question | errormessage: undefined reference to '...' ??? Thank you very much, that was the reason! |
2013-10-21 14:51:09 -0600 | asked a question | errormessage: undefined reference to '...' ??? Hi, I get the error message mentioned above when I try to compile the following (extract from my VideoProcessor.cpp file): ... ... The two error messages say:
while the corresponding header file looks the like that: ... private: bool readNextFrame(cv::Mat& frame); void writeNextFrame(cv::Mat& frame); public: ... void run(); ... I included the header file and all other methods in this class work very well. Thanks |
2013-10-07 16:35:14 -0600 | asked a question | BoundingBoxes with CannyEdgeDetector Hi, I tried to modify the code presented in the tutorial you can find following the link below. The thing is about finding the edges (or contours) of an image and then building bounding boxes around the ojects surrounded by a contour line. I found out that the contour lines of the gray image are often not giving me the desired result and I think I could get a better result if I would find the contour lines of an canny filtered image. I tried the following: But when I try to run the code an error occurs in line 78 ( findContours(checkitout,contours,0,1) ) telling me "OpenCV Error: Unsupported format or combination of formats ([Start]FindContours support only 8uC1 and 32sC1 images), file ... (more) |
2013-10-02 08:38:43 -0600 | commented question | Run Asus Xtion with HighGUI - HOWTO?! thank you very much! It works now :). |
2013-10-01 08:08:04 -0600 | commented question | Run Asus Xtion with HighGUI - HOWTO?! Thanks for the quick reply! BuildInformation() gave me the following: with getBuildInformation() Video I/O: OpenNI: NO OpenNI PrimeSensor Modules: NO sorry for the stupid question, but does that mean it is not supported or just no activated? And when I reinstall opencv, do I have to uninstall the current version first or can I just rebuild it using cmake? |
2013-10-01 07:32:01 -0600 | asked a question | Run Asus Xtion with HighGUI - HOWTO?! Hi, I am trying to make the Asus Xtion pro live work with my computer. I am using ubuntu 12.04 with Opencv 2.4.6.1. I have been trying this for quite some time now but I cannot make it work. I downloaded the the tools from http://www.asus.com/Multimedia/Xtion_PRO_LIVE/#support_Download_5 a. PrimeSense Software Package 20.4.2.20 : 1. OpenNI Framework (Version 1.5.2.23) 2. Sensor DDK (version 5.1.0.41) 3. NITE (version 1.5.2.21) 4. USB driver (version 3.1.3.1) Then I followed the installation instructions and tried to run the Xtion in NiViewer, which works fine. After that I wanted to make the example code on http://docs.opencv.org/doc/user_guide/ug_highgui.html run. But when I try to run the code, I get the the error Message "Can not open a capture object", which is cause by This is what is mentioned in 2. on http://docs.opencv.org/doc/user_guide/ug_highgui.html. How can I change the CMake variables in Codeblocks? I have no CMakeLists.txt as I just created an empty project and added a .cpp file. Thanks! |