The Weather at Howhill

Webcam - Evaluation

During May 2004 I had the opportunity to test three network cameras for use as the Howhill Weather Webcam.

These cameras were:

All cameras were set up looking at the same view and each camera was adjusted to produce the best that it could whilst maintaining sensible file sizes for a 640x480 pixel web page image.

Below is a selection of images captured from the cameras. Apart from being resized for display on this page no other image enhancement or processing has taken place. Clicking on an picture will open a window containing the full size image as captured from the camera.

Further sets of images are available.

Axis 2100 (8 mm)	Axis 2110 (4 mm)	NetCam (8 mm)
08:25 - 21 May 2004

Axis 2100 (8 mm)	Axis 2110 (4 mm)	NetCam (8 mm)
17:10 - 22 May 2004

Axis 2100 (4 mm)	Axis 2110 (8 mm)	NetCam (8 mm)
20:40 - 22 May 2004

Axis 2100 (4 mm)	Axis 2110 (8 mm)	NetCam (8 mm)
13:40 - 24 May 2004

Summary

Camera Overview

Axis 2100 and 2110 Both of these cameras are small and light weight in plastic housings. Image control is limited to size, compression, brightness, colour level and white balance. Both can stream moving images at moderate frame rates over a network connection. The burnt in caption is limited to a short phrase with fixed format date and/or time information. The position or colours used by the caption cannot be changed. Both Axis cameras can be configured with any modern web browser, occasionally the information on the displayed pages would not truly reflect the actual camera configuration causing confusion. The later firmware (v2.40) seems better in this respect or it could be that the operator has learnt to avoid the ways leading to confusion. Some temperature related focus drift was noticed with the lens supplied with the Axis 2100 camera.

StarDot Technologies NetCam
A little larger and heavier than the Axis cameras but the housing is of all metal construction. In addition to the image control features of the Axis cameras the NetCam also allows the actual exposure to be controlled and selected parts of the image, on a 5x5 grid, to be included or excluded from the auto exposure algorithm. This means, for example, you can reduce the effect a bright sky has on the exposure. Image gamma and "haze" are also adjustable and an offset can be applied to the auto white balance to compensate for strange lighting conditions. The NetCam does not stream moving images particularly well, around 1 frame per second at 320x240 or 1 frame every 7 seconds at 640x480 pixels. The caption is generated from a user defined format string with many variables available for display, from individual date and time components to internal camera settings. The foreground/background colour and position of the caption can be configured and there is a selection of fonts available. Detailed configuration is again via a modern web browser no problems where encountered where the pages did not show the true configuration of the camera.

Conclusion

The StarDot Technologies NetCam consistently produced better images than either of the Axis cameras. The NetCam gave sharper, more realistic colours and was more tolerant to the wide range of lighting conditions that occur with exteriors views. The ability to adjust the gamma and those parts of the image which are used for the exposure algorithm also extends the range over which the camera produces acceptable images.

Very little difference was seen between the two Axis cameras and those differences can be attributed to the different lenses supplied with each camera. The lens supplied on the Axis 2100 is very basic and can only be adjusted for focus. The Axis 2110 lens is varifocal with adjustable iris and focus. Axis images with "(8 mm)" in the caption are using this lens stopped down and adjusted to approximately the same field of view as the 8mm fixed focal length lens supplied with the NetCam.

For overall image quality the NetCam is far better than the Axis models but does not really stream moving images, this is not a problem with hourly still images uploaded to a web page. The sensitivity of the NetCam is a little lower than the Axis cameras and combined with stopping the lens down to f16 for daytime use it means that the NetCam produces a black frame when the Axis cameras are still showing a dull and noisy image.

All cameras can support a modem directly and can automatically dial up an internet connection and upload an image. The NetCam can also upload a file containing its current IP address, so when used with a dial up ISP that uses dynamic IP address's (most in the UK) you can easily find out what it is and connect to the camera whilst it has dialed up for configuration changes etc. The Axis cameras do not support such a facility and are really geared for static IP address's. The NetCam seemed remarkedly reluctant to hang up the telephone line once it had dialed up. How ever this may have been a feature of the ISP I was using to test, this ISP sends an echo request every 20 seconds or so which may have been causing the NetCam to think that there was valid traffic on the link and thus not to drop the line. Shortage of time for this testing meant that a different ISP and/or a configuration change was not tried in an attempt to resolve the problem.

Additional Information

Added 26 March 2005
After having a Netcam installed for a while I have to report that the initial picture quality has deteriated. The instructions do warn against direct sunlight and damage to the sensor from such is not covered by the warranty. Unfortunately the winter sun does cross the frame and it has left several pink trails across the image. Not only that but the sky appears to have left its mark as well.

This is a little disappointing, Axis 2100 cameras belonging to Cybermoor [] do not appear to have suffered either of these problems. The Bayles camera does catch the morning sun just like the Howhill one. It would be interesting to try the Axis 211 [] network camera, this came to the market a month or so after I finished the above evaluation. Both the Axis 2100 and 2110 have now been discontinued.

Howhill Weather - Webcam

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Updated:
Mon 5 Jan 2009, 16:34 GMT