OpenCV Examples Part 1

Nov 4, 2008 | Tags: OpenCV | del.icio.us del.icio.us | digg Digg

7. Conclusion

This article covered some basic OpenCV samples. We will use a lot of concepts from these samples in the rest of our life.

The package contains code samples used in this article is available for you to download. If you encounter problems with compiling or running the samples, feel free to contact me [at] nashruddin.com.

Further readings:

Related Articles

Recommended Books

book cover Learning OpenCV: Computer Vision with the OpenCV Library
By: Gary Bradski, Adrian Kaehler
This book is the "de facto" OpenCV User's Manual. It provides a practical, pragmatic, accessible book on computer vision, with algorithmic explanation and concrete example code snippets. Written by the creators of OpenCV, no doubt you should obtain a copy.

book cover Machine Vision: Theory, Algorithms, Practicalities (Signal Processing and its Applications)
By: E. R. Davies
This book provides a solid and concrete foundation to computer vision from engineering point of view. Use Learning OpenCV from Gary Bradsky to learn how to use OpenCV, and use this book to understand how OpenCV works behind the screen.

The Downloads

6. Access Image Data  

19 Comments

foxky on Jun 16, 2008:

Thanks a lots. It's very helpful.

Nash on Jun 17, 2008:

Thanks. glad you like it.

Jyoti Gupta on Oct 20, 2008:

Hi Nashruddin,
I am woking on openCV & come across ur site,very gud work.I am stuck somewhere and need help,I am dropping you mail,plz reply with some idea & solution on the problem.

Amine on Dec 14, 2008:

Slm, nashruddin, thanks a lot great work keep going!

Nash on Dec 20, 2008:

Guys,
I have posted OpenCV Examples Part 2. Take a look and give me some feedback.

Kaveh on Dec 29, 2008:

Hail to you, it was very usefull for me, thanks a million, good job

Deena on Apr 1, 2009:

Hi Nash,

I am newbie in openCV, I saw your website and think it is very interesting.
I am working on this project.
I need your opinion if I want to divide an image into parts like say, divide to 2 parts(pieces) of an image or 4 pieces and etc,

what function should i use in the programming? pls help, thanks.

Nash on Apr 1, 2009:

Hi Deena,
You can use cvSetImageROI to set Region of Interest. See this post for examples:

http://nashruddin.com/OpenCV_Region_of_Interest_(ROI)

Deena on Apr 2, 2009:

thanks, i'll try it out..
keep up the good work!

Innocent on Apr 11, 2009:

Hi every body. Is there anyone that knows how to auto snapshoot a member while login in a membership webpage? The pict will be save in a distant server in a database (MySql). I am familiar with PHP. Thanks in advance

Indhu on Apr 21, 2009:

Came across this site when i was searching for extracting part of an image. Found it very very useful.Thank you

Indhu on Apr 23, 2009:

Hi Nash,
Do you have any example code with cvfIndDominantPoints() ?

Nash on Apr 23, 2009:

Unfortunately I don't have it yet.

achu18 on Jun 2, 2009:

Hi Nash,
Great work, the tutes are very helpful. Is there anything on your website that deciphers the IplImage.imageData i.e. how the channels r interconnected and how to filter out/manipulate colors that you chose? Any help would be appreciated
Cheers

Nash on Jun 2, 2009:

To get each channel as a separate image, use cvSplit function. e.g:

IplImage *img = cvLoadImage("ery.jpg", 1);

IplImage *r = cvCreateImage(cvGetSize(img), img->depth, 1);
IplImage *g = cvClone(r);
IplImage *b = cvClone(r);

cvSplit(img, r, g, b, NULL);
Now you have three images for each channel, and you can hack them just like any regular image.

Hayder on Nov 11, 2009:

A Logical Error in ur code:

r = data[i*step + j*nchannels + 0];
g = data[i*step + j*nchannels + 1];
b = data[i*step + j*nchannels + 2];

its basically

b = data[i*step + j*nchannels + 0];
g = data[i*step + j*nchannels + 1];
r = data[i*step + j*nchannels + 2];

Simple BUT Logical

Huy Vo on Mar 20, 2010:

That's a great of work, thank you million time.

Nikhil on Jun 8, 2010:

HI
i am working on open CV.
i need to access images from a remote databases.
how to code it down.

Nash on Jun 9, 2010:

Use libcurl to fetch the images from an HTTP server.

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In this page

  1. Introduction
  2. Load an Image
  3. Retrieve Image Properties
  4. Copy an Image
  5. Convert RGB to Grayscale
  6. Access Image Data
  7. Conclusion
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