I have a project about Character Recognition (using openCV libraries).
I don't know how to detect character in text image.
Can you recommend some methods to do this?
Thanks all!
Here is a tutorial, it is dated and uses the C-style API though. This online book has a bunch related to OCR using OpenCV in chapter 5. Many people have done work intergrating tesseract (an OCR engine) with OpenCV, so you might want to check that out.
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I was interested in symbol recognition recently and I start to read about it in the Internet. I got more information about preprocessing and segmentation stages, but all of it is just prestage for transformation from image to string. And all notes from Internet led me to using ready solution, like Tesseract, which do all works behind interface. However, I interested in detailed description of this process and I want to get all steps of this transformation.
Can anybody give me some links to exhaustive literature or articles about this theme? For example, Tesseract image_to_string() function algorithm. I will thankful for any help
The most straightforward way is the github page of Tesseract, especially the Wiki page of Tesseract.
Or if you want to recognize specific symbol, you can make your own recognizer using neural networks, follow this step-to-step tutorial.
I used Tesseract and trained it with complete word as character, How chinese OCR are doing. But this kills me to make my own fonts and its a time consuming and slow process. This approach is good for some scenario but I wanted to trained tesseract based on arabic characters.
Or Suggest me which can help me developed my own arabic ocr with or without Tesseract.
I have researched on OpenCV but it didnt go well.
I will highly appreicate your quick response.
Tesseract has pre-trained files for a lot of languages, here is the Arabic one.
This is a very old question, but for whoever is looking for the same, now tesseract 4 comes with pre-trained Arabic data alongside many other languages which can be found here
And here is a demo of Arabic OCR based on tesseract 4, you can see how accurate it becomes now.
I have seen numerous examples and sample code for detecting emotions from a human face. I am in desperate need of some algorithm to change expressions. I am a new OpenCV learner. I am also confused if this image manipulation can be done using opencv ? Can functions such as warpaffine() be used for this ? If shall be grateful if someone can guide me in steps how to perform this eg. input a neutral face emotion and convert it to smile ?
Try using FaceAPI, it is free to use for non-commercial purposes and works brilliantly. It is well documented and easy to use.
I'm new to video processing and I'm wondering what libraries I can use to do things like detecting letters, drawing boxes around them and so on. If you can name me a couple of good ones, I'd appreciate it very much!
OpenCV: (Open Source Computer Vision) is a cross-platform library of programming functions for real time computer vision.
It provides interfaces for both C and C++ programming laguages.
As for detecting the text region and drawing boxes around it, you can take a look at this article, which explains how to do this stuff using OpenCV. For better OCR capabilities I think that tesseract is the best open source tool available right now.
I've worked on a similar project some time ago and used OpenCV to detect the text region and then tesseract to do proper text recognition.
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.