Is there any specific function that can be used in opencv for skeletonization? Besides, i searched for some time and want to know if opencv implements voronoi-skeleton (seems like there is but is it really are)?
It looks like Voronoi-Skeleton is implemented in the _cvConstructSkeleton() and _cvLee() functions in opencv/src/cvaux/cvlee.cpp.
I haven't seen any official documentation about how to use this functionality in OpenCV. Since cvlee.cpp is in the cvaux folder, I think these may be experimental OpenCV functions.
Related
Can OpenCV seamlessly interact with all cameras that comply with these standards
No it cannot. You need something called a GenTLProducer in order to interact with your camera. Normally your vendor's SDK comes with it. Alternatively, you can use the one from Baumer Here or from Stemmer Imaging Here.
Another option is to use harvesters, which is an open source project that aims to do this. Although you need a GenTLProducer for that as well.
I would like to use Smalltalk (Pharo) to better refactor my image processing and computer vision code/algorithms, written in other languages. I have not found a lot of examples online where Smalltalk is used for processing images (or video frames). I would like to know whether
i) there is an opencv/image/computer vision library available for Smalltalk that is easily installed or
ii) someone could give an example of how to access the pixel data in an image and threshold it using Smalltalk.
For the first question, you can maybe write your own interface using FFI to the OpenCV C-API.
For the second question, I think it's easy to use ImageReadWriter formFromFileNamed: and then can use pixelValueAt: to read the value, threshold, and then write back by pixelValueAt:put:.
There is a recent binding to OpenCV (for Pharo 7 a.t.m.) at https://github.com/feenkcom/gt4opencv
Once I was in need to understand a not documented USB-device (the supplier went bankrupt) I've written a wrapper for FTDI-dll which has traced all the calls with all the data passing in and out.
Now I wonder is there anything similar for OpenCV? Are there wrapper dlls for OpenCV which log all API-calls?
Of course, one could modify code and log all the calls, but is there an option built in OpenCV already?
Thank you for any hint!
I want to do a project involving Computer Vision. Mostly object detection/identification. After some research, I keep coming back to OpenCV. But all of the tutorials are from 2008 (I guess it was big for a bit then). It doesn't compile in Python on the mac apparently. I'm using the C++ framework right out of Xcode, but none of the tutorials work as they're outdated and the documentation sucks from what I can parse.
Is there a better solution for what I'm doing, and does anyone have any suggestions as to learning how to to use OpenCV?
Thanks
I have had similar problems getting started with OpenCV and from my experience this is actually the biggest hurdle to learning it. Here is what worked for me:
This book: "OpenCV 2 Computer Vision Application Programming Cookbook." It's the most up-to-date book and has examples on how to solve different Computer Vision problems (You can see the table of contents on Amazon with "Look Inside!"). It really helped ease me into OpenCV and get comfortable with how the library works.
Like have others have said, the samples are very helpful. For things that the book skips or covers only briefly you can usually find more detailed examples when looking through the samples. You can also find different ways of solving the same problem between the book and the samples. For example, for finding keypoints/features, the book shows an example using FAST features:
vector<KeyPoint> keypoints;
FastFeatureDetector fast(40);
fast.detect(image, keypoints);
But in the samples you will find a much more flexible way (if you want to have the option of choosing which keypoint detection algorithm to use):
vector<KeyPoint> keypoints;
Ptr<FeatureDetector> featureDetector = FeatureDetector::create("FAST");
featureDetector->detect(image, keypoints);
From my experience things eventually start to click and for more specific questions you start finding up-to-date information on blogs or right here on StackOverflow.
Let me add a couple of things. First, I can assure you that the Python bindings to OpenCV work on a Mac. I use them every day.
Many people like OpenCV for many reasons:
The license is good, friendly to integration into commercial products, etc.
It is quite good from a technical stand point. It gives you a reference implementation of state of the art algorithms.
It tends to be quite fast compared to the alternatives (Matlab I'm looking at you).
Like everything in life, it is not perfect:
It is a good example of a software library that is a moving target.
I have a 300 line python program that uses OpenCV and every few
months when a new version of OpenCV is released I have to change it
to adapt to the new function names/calling conventions, etc. The
library does advance, a lot, however it is a pain to have to change
the same program 3 times per year.
It has a learning curve, like computer vision itself, it is quite
technical and not easy to learn.
There are alternatives (with other pros and cons) MATLAB with the Image Processing Toolbox is one such example.
The simplest answer that comes to mind, is to read the example code with a bit of understanding, and to try out if Your ideas work. The api does change, and most of the tutorials are writen for the first versions of OpenCV, and it looks that nobody bothered to rewrite them. Nevertheless the core ideas behind it are not changing. So if You find a tutorial answering Your questions, but written in old API just look in the documentation for modern replacements of used functions. It’s not easy and quick, but looks like it works. If You use the newest (actually 2.3) version, I suggest using both the 2.1 documntation and 2.3 docs + tutorials . You should also look into the samples, which should have been installed alongside the library. There are lots of hints about how to use certain structures and tricks that weren't mentioned in documentation. Finally, don't be afraid to look inside the code of the library itself (if You compiled it on Your own). Unfortunately, thats the only source I know to check for example what code corresponds to which type of Mat object.
We're looking for a package to help identify and automatically rotate faxed TIFF images based on a watermark or logo.
We use libtiff for rotation currently, but don't know of any other libraries or packages I can use for detecting this logo and determining how to rotate the images.
I have done some basic work with OpenCV but I'm not sure that it is the right tool for this job. I would prefer to use C/C++ but Java, Perl or PHP would be acceptable too.
You are in the right place using OpenCV, it is an excellent utility. For example, this guy used it for template matching, which is fairly similar to what you need to do. Also, the link Roddy specified looks similar to what you want to do.
I feel that OpenCV is the best library out there for this kind of development.
#Brian, OpenCV and the IntelIPP are closely linked and very similar (both Intel libs). As far as I know, if OpenCV finds the intel IPP on your computer it will automatically use it under the hood for improved speed.
The Intel Performance Primitives (IPP) library has a lot of very efficient algorithms that help with this kind of a task. The library is callable from C/C++ and we have found it to be very fast. I should also note that it's not limited to just Intel hardware.
That's quite a complex and specialized algorithm that you need.
Have a look at http://en.wikipedia.org/wiki/Template_matching. There's also a demo program (but no source) at http://www.lps.usp.br/~hae/software/cirateg/index.html
Obviously these require you to know the logo you are looking for in advance...