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2019-12-11 12:15:42 -0600 | answered a question | Is there a simple way to see the intensity of each point of an image? If you built the library with Qt support, you have this feature directly in the window where you display the image, it's |
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2013-04-30 17:49:13 -0600 | commented answer | Location of the headers moved? Hi, I made a pull today after long time and after compiling and installing i did notice this change and it is really annoying cause my project is pretty big and with a lot of include to correct. By any chances do you guys know if it is gonna be a "stable" change and if they gonna fix the include directory when installing, so we can have the "compatibility" headers (opencv2\<moduleName>\someHeader.hpp) in the include dir? Otherwise i agree that the workaround @berak proposed is smart and it can save some work (for now...) |
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2013-01-17 07:38:20 -0600 | asked a question | Filter the rows/columns of a Mat Hello, I want to filter out the rows of a Mat according to a mask, a task that may be quite frequent in computer vision. I was wondering what's the most efficient way to do it. Suppose you have a matrix to get the desired filtered matrix. In OpenCV the simplest way, i guess, to do something like that is to build another matrix copying row by row, so something like this: This works just fine, but I was wondering if there is a more efficient method (computationally and/or from memory use point of view), such as for example casting somehow (i'm just fumbling here..) Also, another variant of the same problem is when you have as mask a Any comments? :-) Thanks! S. |
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2012-11-27 09:30:51 -0600 | answered a question | Extrinsics matrix after cv::StereoCalibrate If you are using StereoCalibrate with Kinect1 as Camera1 and Kinect2 as Camera2 then the transformation between the two cameras is |
2012-11-25 04:02:35 -0600 | commented question | Image matching problem I don't know the time constraint of your application, but for example you can switch (temporaly) to the BruteForce method and impose the crossCheck flag, so that you always have two features that match in a reciprocal way. This may be helpful to see if there are some problem in your code. Also if u can share part of the code where u do the matching it would be helpful to see if everything is done correctly. Here is the doc for the BruteForce approach http://docs.opencv.org/modules/features2d/doc/common_interfaces_of_descriptor_matchers.html#bfmatcher-bfmatcher |
2012-11-23 05:34:20 -0600 | commented answer | OpenCV4Android and parallel code thanks! I don't want to abuse your kindness but i'd have another question: what about renderscript? It seems google is preferring it to Opencl for android gpu computing. Is there any work done/planned in that direction? |
2012-11-22 01:29:10 -0600 | commented answer | OpenCV4Android and parallel code Thank you very much. Is there a plan to allow support for OpenCL in the future? |
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2012-11-21 17:11:47 -0600 | commented answer | How to create a binary image mat? I don't know what else could be. What other values did u get? Can u somehow compare them with the original ones in the grayscaleMat? |
2012-11-21 15:44:58 -0600 | answered a question | How to create a binary image mat? Try to use instead of CV_THRESH_BINARY. S. |
2012-11-21 14:46:43 -0600 | answered a question | lkdemo don't work . It could be either:
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2012-11-21 12:22:48 -0600 | asked a question | OpenCV4Android and parallel code Hi, I have 2 questions concerning OpenCV4Android:
Thank you! Simone |
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2012-11-13 05:07:49 -0600 | answered a question | Is it possible to extract a 3D Cad model from pictures like 123D? Hi, the answer by @Ben is a good direction to search. I suggest you also take a look to this kind of systems (and the relevant pubblications cited in the website
They both give you as output points. I guess you prefer to have some sort of geometric surfaces fitted to that data, which may be the starting point for you. Also it depends a lot on the prior knowledge you have about the shapes you want to recover: if you know that the objects are man-made with simple geometric shapes like then you can set and impose some constraints during the 3D reconstruction so that you get as output geometric primitives (box planes and so on) describing your object. For example this may be a first point to start. Hope it helps S. |
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2012-11-12 08:38:30 -0600 | answered a question | MatOfDMatch how can it be used? Hi, you can convert the MatOfDMatch to a Java list and then go through it with the List iterator as you do in a any Java program: You can check the documentation of DMatch here, basically every DMatch element corresponds to a match between the two images: when comparing only two images (trained is just a simple list of descriptors) then you only need the queryIdx and trainIdx fields which indicate the index of the feature in the query image (in your case keypoints) and in the train image, respectively. In case your trained descriptors are a list of list of descriptors (so you are comparing your image to a set of images) then the imgIdx will tell you the index of the image that has the match. Hope it helps S. |
2012-11-12 08:22:05 -0600 | commented question | Initializing static cv::Mat with cv::Mat::zeros causes segmentation fault I tried to reproduce it but I have gcc 4.5.2 and i don't have any issue with that code. I don't know if it is just a version number problem. Anyway, have you tried to initialize the matrix like static cv::Mat staticMatTwo = cv::Mat::zeros(3,3,CV_32FC1); S. |
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2012-11-11 12:14:09 -0600 | commented answer | Problem installing the right Manager.apk and Binary_pack.apk for OpenCV4Android If you are using eclipse then you can go to Window > AVD Manager and then you see the list of emulators you have created. Select the one you want to use and click Edit. On the third box of the windows that pops up you can see the CPU of the Emulator. check this http://developer.android.com/tools/devices/managing-avds.html Otherwise you have for sure installed the Android SDK (http://developer.android.com/sdk/installing/index.html), go to that directory from the windows prompt, go to tools directory and run the above command |
2012-11-11 10:50:30 -0600 | answered a question | Problem installing the right Manager.apk and Binary_pack.apk for OpenCV4Android Hi, from the windows shell or a linux terminal you can run this command with your device attached to your PC this will return the type of cpu your device has, and then you can load the correct version of the manager and of the library S. |
2012-11-11 10:15:38 -0600 | answered a question | To save vector "KeyPoint" to file using builtin write function Hi, it's actually simple. In order to save your keypoints This will store your keypoints in a file named keypoints.yml and the node containing the data is named "aNameYouLike". This will be used to read back the keypoints from the file: You may want to check the XML/YAML file storage documentation for more information. Hope it helps S. |
2012-11-08 11:30:48 -0600 | answered a question | cv::Mat divide by last row. Hi, I don't know if it is particularly efficient but you can do the following using repeat This is like doing in matlab. Otherwise another way to do it is to pass element by element and do the division and replace <float> with the correct type of your matrix. Hope it helps. S. |
2012-11-07 04:36:12 -0600 | commented question | Problem loading the jni lib with OCV Manager Ok my bad... I was actually using the trunk version of OCV to build while on the devices i still had the OCV 2.4.3 binary version. As soon as i made everything coherent with the binary version it worked. |
2012-11-06 10:20:12 -0600 | asked a question | Problem loading the jni lib with OCV Manager Hello, I had a simple app for LK tracking that was basically built following and slightly the "Tutorial 2 - mix Java+Native" of a older version of OCV (2.3.x i think). So now I'm trying to update the application in order to use it with the 2.4.3. I succesfully managed to slightly change the code so i can use the 2.4.3 in a static way. Now I'd like to go further and update it to use the OCV Manager. Here come the problems. :( Let me first recall that the architecture of the app is exactly the same as the old sample i mentioned before, so we have 3 files, with the main TrackingActivity, the TrackerBase Class with the threaded structure and the Tracker derived class that implements the method to be called whenever a frame is available. I removed all the code for static loading and added the new way of interacting with the manager to the main activity So far so good. I also changed all the .mk files to resemble those of the official documentation and of the new samples of OCV 2.4.3. When i tried to execute the application (both on real devices and on the AVD) the OpenCV Manager is connected succefully and then when it comes to I get this exception (more) |
2012-11-02 18:37:28 -0600 | commented answer | Building Android Manager from git repository PS My apps are just for research purpose, there won't be anything commercial or public (at least for the moment), so I don't think it's necessary to change the name to avoid any sort of conflicts with the "official" libraries. |
2012-11-02 18:36:06 -0600 | commented answer | Building Android Manager from git repository Hi Kiril and thank you very much for your answer. Ok i get that i don't need to build the Manager, i can use the one from the binary build. And I have been perfectly fine so far working with static initialization of the library. On the other hand, since I'm working with several applications, all using the my own build of OpenCV, I was wondering if i can switch to the Manager way of handling the library with my own build, provided that the Manager can handle that. Therefore, just for the sake of the argument, what should I do to generate my apk? Shall i do a make install when building or what? Thanks! S. |
2012-11-02 11:04:25 -0600 | edited question | Building Android Manager from git repository Hello, I'm upgrading to the new version of OCV4Android and I see that now the library are managed in a different way with the OpenCv Library Manager and I understand the benefits of it. My device cannot connect to the Internet neither have google play so i guess i should proceed as described here My question is: say that I want to compile my own version of OpenCV4Android (eg using always the latest version from the repository or change something in the code), how can I generate the above Manager.apk and binarypack.apk? I successfully followed the instruction from here to compile the code but I cannot find those apk. Yet I can see the source code of the manager in the service folder. Is there any documentation about it somewhere? Thank you! Simone |