More Than Technical

Archive for August, 2009

Hi

I had very high hopes for iPhoneOS 3.1 in the AR arena. With all the hype about it, I naturally thought that with 3.1 developers will be able to bring marker-detection AR to the app-store – meaning, using legal and published APIs. A look around 3.1′s APIs I wasn’t able to find anything that will allow this.

Not all AR is banned. In fact AR apps like Layar will be very much possible, as they rely on compass & gyro to create the AR effect. These don’t require processing the live video feed from the camera, only overlaying data over it. This can be done easily with the new cameraOverlayView property of UIImagePickerController. All you need to do is create a transparent view with the required data, and it will be overlaid on the camera preview.

Sadly, to get marker-detection abilities developers must still hack the system (camera callback rerouting), or use very slow methods (UIGetScreenImage). I can only hope apple will see the potential of letting developers manipulate the live video feed.

Roy.

Today I came across a very nice free service called Ring-2-Skype. It lets you register a personal international number from about 40 countries, and whoever calls this number and dials your extension is directed to your Skype account.

The coolest thing is that you can register a number on several countries for the same Skype account. For instance on for USA, one for Peru etc.

And… it’s FREE!

The downside is that the number you get is not direct, but requires you to dial an extension number, so you can’t use it with Google Voice-like services.

UPDATE #1: I discovered a bug with the service – it is incompatible with Skype’s voicemail: meaning the call gets disconnected when the greeting is played. I contacted them and they said it’s a known issue and they are taking care of it. I’ll update the post again once I know this issue is resolved

Hi
OpenCV is by far my favorite CV/Image processing library. When I found an OpenCV port to the iPhone, and even someone tried to get it to do face detection, I just had to try it for myself.

In this post I’ll try to run through the steps I took in order to get OpenCV running on the iPhone, and then how to get OpenCV’s face detection play nice with iPhoneOS’s image buffers and video feed (not yet OS 3.0!). Then i’ll talk a little about optimization

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

Let’s begin
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