getting started with opencv 2.1 - opencv

I'm very new to opencv. Can anyone suggest a source from where I could start learning about the software. Also I want to do image stitching as a part of my project. Can anyone help me out with this?

Books:
"Learning OpenCV" by Gary Bradsky
"OpenCV cookbook"
If you are just beginning, try OpenCV 2.3.1, latest version.
OpenCV documentation has got a collection of nice tutorials for beginners.
Join OpenCV Yahoo group. You can ask your doubts in group or here in stackoverflow also.
Also have a look at samples that comes with OpenCV. That is also a good start.

Related

OpenCV Sample Code in python

I'm trying to get a start on using opencv in python to do some object detection. Are there any example code projects out there?
I've seen some examples that are specific to face detection but they seem to use preprocessed data that I don't know how to generate.
Thanks!
There are a lot of examples, but I would suggest in any case to give a look at the following sources:
http://opencv-python-tutroals.readthedocs.org/en/latest/
http://www.pyimagesearch.com/

Asift and openCV?

Does opencv allows to use ASIFT ?
http://www.ipol.im/pub/algo/my_affine_sift/
The creator published the c++ so I believe it wouldn't be so hard to implement it into opencv
What do you mean by
Does opencv allows to use ASIFT ?
At this moment, ASIFT is not available in OpenCV directly, but it should be a no-brainer to connect the code provided by the ASIFT authors to OpenCV. Probably all you'll have to do is to convert the OpenCV cv::Mat to some specific image format, by accessing Mat::data pointer.
If you are worried about licensing terms, you should contact the ASIFT authors. OpenCV is free to use/modify/redistribute/sell, under a BSD licence. And it seems that it is the same for ASIFT.
And if you are talking about integrating the code into OpenCV, and sending a patch to the dev guys, there is a guide on how to do it here http://code.opencv.org/projects/opencv/wiki/CodeSubmissions and here http://code.opencv.org/projects/opencv/wiki/How_to_contribute and here http://code.opencv.org/projects/opencv/wiki/CodingStyleGuide . I (and many others) strongly encourage you to do it! It seems to be an important addition to OpenCV.
The 2022 update is that ASIFT is in OpenCV v3.4 and higher.
Examples for the latest stable (v4.6):
C++
Python

How To Read numbers from Image using OpenCV 2.1

Previously I posted this question in this forum and as per as experts suggestion, they recommended me to use OpenCV for extracting data from the image.
I'm new to OpenCV, basically I learnt to install OpenCV 2.1 with Visual Studio 2008 and then I worked with simple programs like to load the images, invert and save images.
Then I'm trying to read the numbers from the image. I searched a lot in Google and OpenCV tutorials PDF, I didn't get any solution.
Please can anyone guide me about this?
Or a simple walkthrough for reading the numbers from the image..
Thank you..
A example of a basic OCR with OpenCV:
http://blog.damiles.com/2008/11/basic-ocr-in-opencv/

OpenCV for iOS graphics app

I want to create a photo and video manipulation app for the iPad. The app would effect the imagery in various ways (using canny edge detection or bilateral blur for instance).
I saw some very interesting examples of canny edge detection using OpenCV, but is OpenCV the right tool to be looking into if I want to create a graphics app like this?
If so can anyone recommend some good reading materials to get me started.
Thanks for reading!
Yes, you certainly can use OpenCV on iOS. You simply cross-compile the code and include it in your project. OpenCV can easily do what you describe, and much more.
O'Reilly has published a great book on OpenCV, which is probably the best way to get up to speed. It explains the methods and how to use them, with plenty of sample code and images.
Learning OpenCV, Gary Bradski, Adrian Kaehler, O'Reilly 2012
There are a few sample projects around:
Sample OpenCV on iOS project
There are also numerous build scripts etc but note that they are probably not the latest version (2.4).

How to use Opencv for Document Recognition with OCR?

I´m a beginner on computer vision, but I know how to use some functions on opencv. I´m tryng to use Opencv for Document Recognition, I want a help to find the steps for it.
I´m thinking to use opencv example find_obj.cpp , but the documents, for example passport, has some variables, name, birthdate, pictures. So, I need a help to define the steps for it, and if is possible how function I have to use on the steps.
I'm not asking a whole code, but if anyone has any example link or you can just type a walkthrough, it is of great help.
There are two very different steps involved here. One is detecting your object, and the other is analyzing it.
For object detection, you're just trying to figure out whether the object is in the frame, and approximately where it's located. The OpenCv features framework is great for this. For some tutorials and comprehensive sample code, see the OpenCv features2d tutorials and especially the feature matching tutorial.
For analysis, you need to dig into optical character recognition (OCR). OpenCv does not include OCR libraries, but I recommend checking out tesseract-ocr, which is a great OCR library. If your documents have a fixed structured (consistent layout of text fields) then tesseract-ocr is all you need. For more advanced analysis checking out ocropus, which uses tesseract-ocr but adds layout analysis.

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