Friday, July 31, 2009

First impression on iPhone 3GS


Recently I got a chance to try iPhone 3GS.

I executed Camera application to see how iPhone's camera module is improved.
Well, I felt no change in image capture mode except auto focusing. The preview is still in 15 fps and there is no great improvement in its quality.

In video recording mode, the frame rate of preview increases to 30 fps (it looks like 30 fps). The video quality is not bad and I think preview quality is better in video recording mode.
The video resolution is 640x480 and frame rate is 30 fps.

When I captured a video with the iPhone in vertical, the video's specification in Quicktime player was 480x640 and it was played in vertical. But, when I played the same file in MPlayer or VLC player, the video is played in horizontal and the resolution was 640x480 ( See the screen capture images below. Click them to enlarge).

The Quicktime player --->


MPlayer -->

Apple seems to insert the information about orientation, which is available from the built-in accelerometer, in the video file. So, the recorded video is originally 640x480 resolution and Quicktime may rotate it based on the orientation information. Apple is already doing this in still image capture.

In my opinion, auto-focusing is not welcomed in computer vision jobs since it changes the focal length of the camera and this breaks the assumption of the fixed focal length, which is a very common in computer vision papers. I hope there is a way to turn off it for augmented reality applications.

Hey, Apple. Why don't you open the interface to video camera control ? It may allow developers to make much more interesting applications....

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