Head Pose Estimation with OpenCV & OpenGL Revisited [w/ code]

So I was contacted earlier by someone asking about the Head Pose Estimation work I put up a while back. And I remembered that I needed to go back to that work and fix some things, so it was a great opportunity.
I ended up making it a bit nicer, and it's also a good chance for us to review some OpenCV-OpenGL interoperation stuff. Things like getting a projection matrix in OpenCV and translating it to an OpenGL ModelView matrix, are very handy.
Let's get down to the code.
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Hand gesture recognition via model fitting in energy minimization w/OpenCV

hands with model fittedHi

Just wanted to share a thing I made - a simple 2D hand pose estimator, using a skeleton model fitting. Basically there has been a crap load of work on hand pose estimation, but I was inspired by this ancient work. The problem is setting out to find a good solution, and everything is very hard to understand and implement. In such cases I like to be inspired by a method, and just set out with my own implementation. This way, I understand whats going on, simplify it, and share it with you!

Anyway, let's get down to business.

Edit (6/5/2014): Also see some of my other work on hand gesture recognition using smart contours and particle filters

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20-lines AR in OpenCV [w/code]


Just wanted to share a bit of code using OpenCV's camera extrinsic parameters recovery, camera position and rotation - solvePnP (or it's C counterpart cvFindExtrinsicCameraParams2). I wanted to get a simple planar object surface recovery for augmented reality, but without using any of the AR libraries, rather dig into some OpenCV and OpenGL code.
This can serve as a primer, or tutorial on how to use OpenCV with OpenGL for AR.

Update 2/16/2015: I wrote another post on OpenCV-OpenGL AR, this time using the fine QGLViewer - a very convenient Qt OpenGL widget.

The program is just a straightforward optical flow based tracking, fed manually with four points which are the planar object's corners, and solving camera-pose every frame. Plain vanilla AR.

Well the whole cpp file is ~350 lines, but there will only be 20 or less interesting lines... Actually much less. Let's see what's up
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Quick and Easy Head Pose Estimation with OpenCV [w/ code]

Update: check out my new post about this http://www.morethantechnical.com/2012/10/17/head-pose-estimation-with-opencv-opengl-revisited-w-code/

Just wanted to share a small thing I did with OpenCV - Head Pose Estimation (sometimes known as Gaze Direction Estimation). Many people try to achieve this and there are a ton of papers covering it, including a recent overview of almost all known methods.

I implemented a very quick & dirty solution based on OpenCV's internal methods that produced surprising results (I expected it to fail), so I decided to share. It is based on 3D-2D point correspondence and then fitting of the points to the 3D model. OpenCV provides a magical method - solvePnP - that does this, given some calibration parameters that I completely disregarded.

Here's how it's done

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GeekCon 2009: RunVas - Our project [w/ video, img]

runvasHi everyone

In the last weekend I attended GeekCon 2009, a tech-conference, with a friend and colleague Arnon (not Arnon from the blog, who recently had a birthday - Happy B-Day Arnon!). Each team that attended had to create a project they can complete in 2-days of the conference. Our project is called "RunVas", and the basic idea was to let people run around and paint by doing so. We wanted to combine computer vision with a little artistic angle.

Here's some more details
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iPhone camera frame grabbing and a real-time MeanShift tracker


Just wanted to report on a breakthrough in my iPhone-CV digging. I found a true realtime frame grabber for the iPhone preview frame (15fps of ~400x300 video), and successfully integrated this video feed with a pure C++ implementation of the MeanShift tracking algorithm. The whole setup runs at realtime, under a few constraints of course, and gives nice results.

Update: Apple officially supports camera video pixel buffers in iOS 4.x using AVFoundation, here's sample code from Apple developer.

So lets dig in...

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