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Image processing

The shots from the webcam at night show a lot of noise, as its not really designed for low light operation. In fact, it is generally difficult to see much more than the glow and sometimes the hint of a steam plume amongst all of the noise.

The US Forest Service Volcanocam is actually a Sanyo VCC-4594 camera. It has an Infra-red (IR) cut-off filter which is automatically removed when the light levels drop below 0.6 lux illumination level for colour images, and it switches to b&w mode with a claimed sensitivity of 0.03 lux.

This is why the camera becomes sensitive to the near-IR glow from the lavadome and also suggests that removing the colour noise from the images (which are actually b&w images at night time) should help to clear up the view.

The work flow that I use for the Volcanocam images is a multi-step process, partly automated by using pre-recorded Photoshop actions and illustrated below with images from the night of 13/14 May 2006.

1. Download images and rename files to correspond to the date and time they were recorded.

 

2. Process each image using a noise filtering program (Neat Image) to remove the bulk of the colour noise.

3. Convert the de-noised images to black & white

4. Enhance the brightness and levels in the images to bring out the maximum amount of detail in the "glow".

5. Stack each processed image on a daytime image of the mountain to provide a reference point for day-to-day comparisons.

6. Convert the batch of processed images to an animation as a compressed MPG file (using Pic2Ani), then convert that file into Macromedia Flash format using SwishVideo.

For information about the software mentioned above  please consult the Links page.