N900 VGA camera

Hardware

The N900 front camera is a VGA camera from ST microelectronics.

The datasheet lists the following specs.

  • Size: 4.5×4.5×2.5 mm
  • Resolution: 640×480
  • minimum illumination 7 lux.
  • SNR at 100 lux 34 dB
  • Field of view: 66 degrees horizontal, 78 degrees diagonal.

This is connected via a multiplexor to the single camera bus on the CPU, along with the main camera. The two cannot be used at once.

Software

The driver presents the camera as a video4linux device - /dev/video1.

This camera had severe performance problems under the original software release. (PR1.0) With PR1.1, released in January 2010, in very good light, the picture was acceptable. In normal room light, the performance remained lower than would be hoped.

With the release of PR1.2, this has improved further, being generally adequate.

Also, with the release of PR1.2, Skype Video began to work, using the VGA camera. Little other software uses the front camera - mirror provides a real-time image of what the camera is showing, and mplayer can also use the camera as a video4linux device.