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2014-12-09 13:57:50 -0600 | marked best answer | const float union ptr in Bradski & Kaehler's “Learning OpenCV” Example 3-9 In "Learning OpenCV" by Gary Bradski & Adrian Kaehler there is a section on the CvMat matrix structure that contains the following example code (it is Example 3-9: Summing all the elements in a single-channel matrix) There are a couple of things I do not understand about this code, but they may be the result of me not using C for many many years rather than OpenCV questions.
instead of taking |
2013-10-28 07:59:41 -0600 | answered a question | Why would video files not open in OpenCV (both C & C++ APIs)? It appears that, following advice from Tobias Senst on a stackoverflow answer, I needed to build OpenCV on my local machine rather than rely on the DLLs that are provided with the standard distribution. It has been a headache to get OpenCV to build locally (see here, here, and here) but now that I reference to a copy of OpenCV 2.4.6 that was built on this machine I can open the video files. I have no idea why this works, why it is not mentioned in the requirements, why others are not more frequently having this problem, nor what is failing with the default deployment, but at least I have it fixed. |
2013-10-28 03:58:31 -0600 | commented question | Where are the correct include directories for OpenCV projects using a local build / self-build of OpenCV? Thanks @berak, that works. If you copy that advice into an answer I'll mark it as such. |
2013-10-27 13:12:45 -0600 | received badge | ● Student (source) |
2013-10-27 05:39:58 -0600 | asked a question | Where are the correct include directories for OpenCV projects using a local build / self-build of OpenCV? I'm trying to debug a frustrating problem whereby I cannot load video files in OpenCV. One suggestion is to abandon the OpenCV pre-built libraries and instead build OpenCV on the same machine as the failing project. That is what I am now trying to do. In the OpenCV Quick Start about how to build applications with OpenCV inside the Microsoft Visual Studio one important step is to add the additional include directories to the project property sheet by opening the project's property pages, navigating to In the pre-built OpenCV distribution Having generated with CMake and built with Visual Studio 2012 the latest version of OpenCV on my machine (though perhaps unsuccessfully) I cannot find What step, flag, etc. did I omit in order to generate place it correctly on my machine? Why are the (N.B. I'm using CMake 2.8.12 and Visual Studio 2012 on a Windows 8 machine.) |
2013-10-27 05:09:29 -0600 | asked a question | 404 Not Found from bug reporting site The OpenCV homepage includes a link titled "Report a bug" to http://code.opencv.org/projects/OpenCV/wiki/WikiStart#Creating-new-tickets. I get the HTTP '404 Not Found' error from that URL, as I do from http://code.opencv.org/projects/OpenCV/wiki/WikiStart and from http://code.opencv.org/ (which redirects to http://code.opencv.org/projects/opencv/wiki) Where should we report suspected bugs? |
2013-10-27 04:32:50 -0600 | asked a question | Plethora of CMake errors about absolute and relative destinations Having downloaded the latest OpenCV source code from github on the 26th of October 2013 I have run CMake (cmake-gui 2.8.12) first 'Configue' and then 'Generate'. Generating the build directory throws a bunch of errors, starting with The first group I think it is safe for me to ignore, they look like this:
But the last list of errors has me more worried. What are these? Should I act on them? How should I fix them?
========== EDIT =========== I wonder if the problem here is that the CMake value (N.B. I have added this as an OpenCV issue/bug.) |
2013-10-25 15:29:00 -0600 | commented question | Why would video files not open in OpenCV (both C & C++ APIs)? It has opencv_ffmpeg246.dll in there already, should that do? |
2013-10-25 12:10:27 -0600 | asked a question | Why would video files not open in OpenCV (both C & C++ APIs)? I am swapping from EmguCV to OpenCV so that I can try some of the OpenCV functions that are not yet wrapped by EmguCV. However I'm failing to load my simple test video file, which loads without issue in EmguCV. Looking at the EmguCV source code I notice that they call the OpenCV C functions rather than C++ to initialise capture from a file (or a webcam) so I wrote the following test code (with help from stackoverflow). Here is my simple code When I run this I get the output
This happens regardless of the file, i.e. it happens for "sample.wmv", "sample.avi", and even one of the OpenCV sample files "tree.avi". Why? What is going on? (I'm running OpenCV 2.4.6 on a Windows 8 and a Windows 8.1 machine.) |
2013-10-17 18:19:54 -0600 | asked a question | 'min (& max) not a member of std' errors when building OpenCV 2.4.6 on Windows 8 for Visual Studio 2012 I'm trying to build OpenCV 2.4.6 on Windows 8 in Visual Studio 2012. Having downloaded the source from https://github.com/Itseez/opencv I generate (leaving the default configuration) using cmake and then load the resulting file error C2039: 'max' : is not a member of 'std' C:\OpenCV2.4.6\3rdparty\openexr\Imath\ImathMatrixAlgo.cpp 1094 1 IlmImf One fix for errors like this (e.g. in this answer on StackOverflow) is to add Am I missing something out in the configuration step? Is there some path setting etc. missing on my machine? Why am I getting these errors and how should I fix them? ========== EDIT ========== Looking at the directory path this appears to be a problem with one of the 3rd party dependencies, OpenEXR. Looking on Github it appears to be version 1.7.1 of OpenEXR that is used in OpenCV 2.4.6. The instructions in the OpenCV's Quick Start Installation on Windows state:
so I downloaded the OpenEXR 1.7.1 source code release and extracted the resulting files putting the directory Then I ran cmake and tried to build the resulting Visual Studio solution. Sadly I see the same errors. |
2013-10-17 15:40:17 -0600 | asked a question | How & where to add debugging symbols for Visual C++ OpenCV project I've set up an OpenCV C++ project in Visual Studio 2012. To get it working I have use various project property pages to
The lines of code I'm trying to debug are more-or-less the same as those in the sample code given for the but I am opening a file Something's going wrong so I want to check what the properties are on "Information not available, no symbols loaded for opencv_highgui246d.dll" I'm unfamiliar with setting up C++ projects in Visual Studio (I've been using mostly C# for years now); what do I need to do to enable this debugging? Do I have to build OpenCV myself (and if so what output should I use where) or are there more files I can copy over and include in my build? |
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2013-10-14 09:45:26 -0600 | commented answer | Why is the blob tracking code 'legacy'? What's replaced it? Thanks; detection's half the job, CvBlobTrackerAuto tracked them too. Is this now spread across classes? |
2013-10-14 07:19:01 -0600 | asked a question | Why is the blob tracking code 'legacy'? What's replaced it? I was struggling to find where in the OpenCV API the blob tracking code that EmguCV uses is. I think I have found it religated to legacy code: https://github.com/Itseez/opencv/blob/master/modules/legacy/src/blobtrackingauto.cpp Why is it legacy code and where is any blob tracking code APIs that have replaced it? |
2013-10-10 06:57:42 -0600 | commented question | What are the five arguments in the 'How to build applications with OpenCV inside the Microsoft Visual Studio' sample code? berak - sure it's not just a copy-and-paste issue and this was the intended sample code: https://github.com/Itseez/opencv/blob/master/samples/cpp/tutorial_code/introduction/display_image/display_image.cpp |
2013-10-10 05:46:27 -0600 | asked a question | What are the five arguments in the 'How to build applications with OpenCV inside the Microsoft Visual Studio' sample code? I'm following the instructions in How to build applications with OpenCV inside the Microsoft Visual Studio but I'm confused by the sample code. When the author calls the built sample he or she uses the single argument But the first few lines of i.e. the application requires five arguments. If the function requires five arguments then what are they and why is only one supplied? If the function only requires one argument then what is this checking code for? ========== EDIT 1 ========== Actually the more I look at it the more confused I am by the sample code. The tutorial sample code purports to be about loading and displaying an image, but looking at the code listing it is all about videos and Gaussian functions. This tutorial is supposed to be the introduction to getting started with Visual Studio, linked to from the primary OpenCV Quick Start page, I cannot be the first person to try the code. Why is it so different from what it purports to be? ========== EDIT 2 ========== I've submitted this as a documentation bug. |
2013-10-10 05:12:03 -0600 | commented question | CAP_PROP_FRAME_WIDTH undeclared in 'How to build applications with OpenCV inside the Microsoft Visual Studio' sample code Moster, that didn't work. But berak, that works. If you want to add it as an answer I'll mark it as such. |
2013-10-09 11:53:26 -0600 | edited question | CAP_PROP_FRAME_WIDTH undeclared in 'How to build applications with OpenCV inside the Microsoft Visual Studio' sample code I'm following the instructions in How to build applications with OpenCV inside the Microsoft Visual Studio but I'm getting errors from the sample code:
I think the identifiers that are undeclared should (are) declared in highgui so why am I not getting them despite the demo code's Here are the steps I have taken.
I think the identifiers that are undeclared should (are) declared in highgui so why am I not getting them despite the demo code's |