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I am really intrigued by the field of computer vision and the potential it has. Are there any examples (preferably implemented in .NET) which I can study along with a reference book?
Sample Vision Code
Vision Source Code - Carnegie Mellon University
Open Source Computer Vision Library - Sourceforge
Computer Vision Test Images
libsift - Scale-Invariant Feature Transform implementation
C# wrapper for OpenCV
Resources
Computer Vision Online - Computer Vision Online
Computer Vision "Home" - Carnegie Mellon University
Lecture on Vision Systems - Cardiff School of Computer Science
Lectures on Computer Vision Systems - The University of Nottingham Computer Science Department
Feature Detection - Wikipedia Article
Scale-Invariant Feature Transform - Wikipedia Article
Stack Overflow Questions
Where do I learn about Image Processing and Object Recognition?
Image Processing Textbooks?
Computer Vision References
OpenCV (Open Computer Vision) is the most popular library, and it has been wrapped for C#:
http://www.codeproject.com/KB/cs/Intel_OpenCV.aspx
Some discussion about this wrapper and the library in general is here:
http://coolthingoftheday.blogspot.com/2008/08/opencv-open-source-computer-vision-for.html
-Adam
While the OpenCV library is interesting to use, it doesn't offer a lot of transparency as you learn. If you're interested in actually learning about the field, I would recommend looking into low-level image processing libraries and implementing your own Computer Vision applications. Once you've coded your own basic CV applications, using the OpenCV library becomes a lot easier. I would suggest the following topics to advance quickly through the basics:
sobel operators for edge detection
trying your hand at color segmentation
reconstructing 3d information from stereo images using disparity maps
Here's a site with some good test images (http://www.cs.cmu.edu/~cil/v-images.html).
I also found a good resource of course slides that cover the majority of these topics at (http://www.cs.nott.ac.uk/~tpp/G5BVIS/lectures.html)
Happy hacking =)
Here's a large collection of code, toolkits, and apps you might find useful
http://www.cs.cmu.edu/~cil/v-source.html
You could start by looking at some of the similar questions on this site:
where-do-i-start-learning-about-image-processing-and-object-recognition
image-processing-textbook
computer-vision-reference
I can also look at these two sites:
http://www.cs.cmu.edu/afs/cs/project/cil/ftp/html/vision.html
http://www.cs.cf.ac.uk/Dave/Vision_lecture/Vision_lecture_caller.html
The sites provide information, tutorials and code examples, even though they are not actively maintained anymore.
There is the OpenCV project on sourceforge with a book that you can get as well. You can see it here. However, that is not a .NET solution it is C
I recommend Open Computer Vision Library. It's much spoken of and looks promising. It even has an O'Reilly accompanying book :)
The Open Computer Vision Library has >
500 algorithms, documentation and
sample code for real time computer
vision. Tutorial documentation is in
O'Reilly Book
I've done a bit of work with SIFT in the recent past and it seems to be a rather interesting modern algorithm for feature detection, which is one of the major (and perhaps more advanced) topics within machine vision. Someone has written a C# library for SIFT with a pretty nice example that can automatically stitch together separate photographs of the same scene. Admittedly, this isn't a very complete answer, and I can't recommend a reference book, but hopefully it should be of some use to you anyway...
The AForge.NET library is pretty good and is written in C#, with the source available here.
Supported features are:
AForge.Imaging - library with image processing routines and filters;
AForge.Vision - computer vision library;
AForge.Neuro - neural networks computation library;
AForge.Genetic - evolution programming library;
AForge.Fuzzy - fuzzy computations library;
AForge.MachineLearning - machine learning library;
AForge.Robotics - library providing support of some robotics kits;
AForge.Video - set of libraries for video processing etc.
The algorithms are maybe not as cutting edge/academic as some of the other answers but a lot of the engineering problems taken care of (getting video into your application, etc).
Related
Does anyone know if there is an open source implementation of oriented Basic Image Features (oBIF)? There's talk about it at http://www.cs.ucl.ac.uk/staff/m.lillholm/or.html and http://blog.kaggle.com/2011/05/04/andrew-newell-and-lewis-griffin-on-winning-the-icdar-2011-competition/. I looked through OpenCV some, but I didn't see anything that looked like this. But maybe I just don't understand all the terminology?
If not, I'd like to try to understand how hard it would be to implement. But I'm new to machine vision, and I'm having trouble understanding the image-specific jargon at the links above ('saddle-like', '2nd order gaussian filter bank', etc - I do know what a Gaussian is -just not a 2nd order filter bank of Gaussian's). What's a good reference for learning these machine vision concepts?
Full disclosure: I would like to know how to use them to compete in this years Kaggle competition (http://www.kaggle.com/c/awic2012) for Arabic Handwriting Recognition. I have more of a Machine Learning background, but I'm interested in using the features that won last years competition.
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I am trying to do some Face Recognition (not detection) stuff using OpenCV. I found this article with some code:
http://www.cognotics.com/opencv/servo_2007_series/index.html
However, this code is written using the older C-style OpenCV API. Does someone have a C++ API version of this using a more recent version like OpenCV 2.3.1?
Update: OpenCV 2.4.2 now comes with the very new cv::FaceRecognizer. Please see the very detailed documentation at:
http://docs.opencv.org/trunk/modules/contrib/doc/facerec/index.html
I have released libfacerec, a modern face recognition library for the OpenCV C++ API (BSD license). libfacerec has no additional dependencies and implements the Eigenfaces method, Fisherfaces method and Local Binary Patterns Histograms. Parts of the library are going to be included in OpenCV 2.4.
The latest revision of the libfacerec is available at:
https://github.com/bytefish/libfacerec
The library was written for OpenCV 2.3.1 with the upcoming OpenCV 2.4 in mind, so I don't support OpenCV versions earlier than 2.3.1. This project comes as a CMake project with a well-documented API, there's also a tutorial on gender classification. You can see a HTML version of the documentation at:
http://www.bytefish.de/dev/libfacerec/
If you want to understand how those algorithms work, you might want to read my Guide To Face Recognition (includes Python and GNU Octave/MATLAB examples):
http://www.bytefish.de/blog/face_recognition_with_opencv2
The relevant publications are:
Turk, M., and Pentland, A. Eigenfaces for recognition.. Journal of Cognitive Neuroscience 3 (1991), 71–86.
Belhumeur, P. N., Hespanha, J., and Kriegman, D. Eigenfaces vs. Fisherfaces: Recognition using class specific linear projection.. IEEE Transactions on Pattern Analysis and Machine Intelligence 19, 7 (1997), 711–720.
Ahonen, T., Hadid, A., and Pietikainen, M. Face Recognition with Local Binary Patterns.. Computer Vision - ECCV 2004 (2004), 469–481.
I'm doing a face recognition project for my engineer's degree, using c++ api. I think that everything regarding face recognition in c++ is fairly straightforward, even simpler than in C (less pointers). To use PCA you have a class named PCA described here. Just use the proper methods and read documentation with understanding. To build the matrix with input data I've created a matrix of proper size, then pasted pictures as rows (use method reshape) into it (there is a method in cv::Mat that lets you to get easily a row of a matrix). You just need to keep sure that base data and tested data have the same parameters (channels, size,etc.)
EDIT:
using namespace cv; //somewhere near top
inserting data to data matrix:
62 Mat reshaped=img.reshape(1,1);
63 Mat dataRow=_data.row(y++);
64 resize(reshaped,dataRow,dataRow.size(),0,0,CV_INTER_LINEAR);
computing pca:
251 _pca(_data,Mat(),CV_PCA_DATA_AS_ROW); //compute pca
252 _pca.project(_data,_vectors); // project original data to new coordinates
As opencv's documentation isn't the best out there, it doesn't hurt to spend some time reading it. Most of the c api functions have their equivalents in c++ api, You only need to do some "write into search window and hit enter" searching. And, there are also tutorials in c++ to get a grip of the c++ api.
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I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to manage it, such as FFT, circular convolution ecc ecc.
I want to learn C++ programming basically for one reason: it's very important in the professional world!!! And I think it's one of the most used to write applications working with audio, especially when it's about real time processing.
Ok, after this small introduction I would like to know first, which are the most used libraries to work with audio processing in c++?? I was longer looking on the web but i couldn't find a lo of working stuff. (I work under linux with eclipse CDT enviroment).
Then I would like to know if there are good sources to learn how to write some working code, such as for example how to write a simple low pass filter. Basically now i will not write real time applications, I would like to start from the processing of a WAV file, or even better an MP3 file, so basically on vectors of samples.
Let's say that basically for now I would like to extract the waveform from an audio file, and save it to a thumbnail or to a PNG image.
Ok, for now I think it's all I would need.
Any ideas, advices, libraries, books, interesting sources about that?
Thanks a lot in advance for any kind of answer.
Giovanni.
I would suggest for you to write your own WAVE file reader and writer in C++, without relying on external libraries. The WAVE format is fairly straight forward, at least if you only intend on supporting the most common wave files.
Then you'll have access to the audio data, which you can easily manipulate in C++. I would recommend starting by modifying the volume, the number of channels to calculating statistics on the audio. Creating a PNG of the audio waveform requires some more advanced C++ skills...
Checkout this link which will give you some information on the available (commercial and open source) audio editing softwares.
Some interesting open source audio editing tools which are written in c++,
Audacity
LMMS
Qtractor
Ardour
Rosegarden
C++ library for audio processing.
SndObj
The Synthesis ToolKit in C++
C++ Code and links related Filters and audio processing..
C++ code for Filter,Audio Processing
Code Guru,Low pass filter
I've used BASS with good results (there's a C/C++ API you can use).
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I am looking to build a new Interactive 3D planning software similar to this one http://www.materialise.com/materialise/view/en/131410-SimPlant.html
I was looking for some expert advise about the best technologies to use to build the different components of the software (ie: UI, Image processing, visualization, 3D, etc.. )
The software need to be able to process the images very quickly and in the same time I need to be able to deliver the software to the market fast, so the technologies used should allow for both rapid application development, and high performance. Any advise would be appreciated
Take a look at VTK (vtk.org) for an general purpose visualization toolkit and the ITK (itk.org)
which is an image analysis toolkit built on top of vtk. Both are BSD licensed.
The Python Imaging Library, PIL, is a good compromise between speed-to-market and good performance (and you can always use scipy and its core part, numpy, to enrich it for more advanced image-processing needs, if you pick Python as your pivot language!-). Similarly, visualization (including 3D) are excellently covered in third-party Python extensions -- check out EPD, the Enthought Python Distribution, for a good idea of what libraries might best help you in such tasks (you can always build your own versions if you don't want to partner with Enthought for commercial distribution... but it might be worth checking them out, as they have excellent commercial contacts as well as tech skills;-).
When and if you want to dip down into C++ for some specific component, Boost.Python, SIP, or Cython will make it child's play to integrate the component into your Python mainstream. For UI &c, PyQt is great...
In other words, while I'm obviously biased, in your shoes I'd unhesitatingly go for Python as the "core" and investigate the various options I've mentioned for visualization, UI, etc, etc. One caveat: for quick time-to-market, stick with Python 2.6: the newest 3.1, while great in many respects, is likely to still miss compatible versions of many third party extensions that will make your life way easier and sweeter with Python 2.6!
ITK is not built on top of VTK, although they are related. One can easily process data with ITK and then switch to a VTK pipeline for the visualization and interaction functionality.
We have built fairly large and complex medical image processing and visualization applications (experimental, surgical planning) in Python using a combination of VTK, ITK and wxPython. The licensing of all these components is such that you can use them in commercial applications.
I tried out the demo application which was pretty impressive. However building it and integrating it with my own code is hard because it's such a large project.
Has anyone successfully used it for their own projects? Was is difficult to build and integrate with your own C++ code?
Link: STLab.
For the interested: there's also a Google Tech Talk clarifying the philosophical ideas behind the project.
ASL is used fairly heavily within Adobe. The layout library (Eve) is used in many Adobe products and variants of it have been in use since Photoshop 5. The property model library (Adam) got a little use in CS4 and will likely be used more in future products. I can no longer speak with certainty because I left Adobe a few months ago and am now working at Google. I still put in some time on ASL and continue to collaborate with Prof. Jarvi and some of his students on the property model library (see the paper on the ASL wiki).
It can be a bit difficult to integrate with your product. The platform libraries in ASL (backends to Adam and Eve for Windows and Mac Carbon) started as some small example code, then the community started to refine it (the Windows port was initially a community effort), then we had some ambition to make it a real, supported library. But then Apple dropped Carbon for 64 bits and Adobe's framework plans changed so we weren't able to leverage our efforts here inside Adobe. Because of this the platform libraries are a little shaky - if your code base is already using a framework you might consider integrating Adam and Eve directly (the API for both libraries is very small). There are two challenges with integrating with a framework. Eve needs good metrics to do a good layout, including things like baselines - getting that from your UI toolkit may be tough. The property model library assumes a strict model/view/controller pattern that most UI toolkits don't obey so you have to do a bit of adapting. Feel free to ask questions on the ASL mailing list. We can also help with building - it really isn't as complex as it seems.
I watched the Tech Talk.. He sort of lost me when he showed the real world example code and then a massively shorter version using his model... I suspect that his implementation, just like anything else, would in practice be bogged down by real world considerations if actually pursued to solve real problems...
That said, it was interesting... The first half of the talk was great... I especially liked his assertion that Generic programming is the mathematics of coding...