Weather Web-Camera Types

The types of web-camera

There are many types of camera available for broadcasting images across the internet. This section describes the different types and their suitability for use as a weather web-camera. Described are USB webcams, Internet Protocol cameras, wireless cameras, movable cameras, video servers and digital still cameras. This section also explains why streaming video is unnecessary for weather web-cameras.

USB Webcams

Most web-cameras available today are USB webcams; which means they are web-cameras that connect directly to a computer using a USB lead. These models are intended for person-to-person communication using products like Netmeeting and Skype.

USB web-cameras are cheap and have wide angle lenses that make them ideal for use as weather web-cameras. However, to function as a web-camera that can be viewed across the internet, they must be connected to a computer which has both specialist driver and web-casting software pre-installed. Furthermore, if a webcam is to provide weather views all day long, then the computer will have to be switched on all day too.

PROS: Cheap and available in most stores.
CONS: Requires an always-on computer with software installed.

Stand alone Internet Protocol cameras

An Internet Protocol camera or IP camera is a web-camera that contains all the parts required to function as a web-camera but, without the need to connect it to a computer to make it work. Instead, the IP camera connects directly to a router; the device for wiring up office and home networks. It can then communicates directly over the internet by itself.

An IP camera features a built-in web server that allows the camera's images to be viewed directly by anyone across the internet. Many IP cameras can also broadcast or stream their output as live video over the internet; which is why IP cameras are used for office and home surveillance. Also, most IP cameras can automatically upload an image to another web site (using FTP) at regular intervals; a feature which makes them ideal as switch on and forget weather web-camera service.

PROS: Ideal stand alone solution for a weather web-camera.
CONS: Very few!

The IP Camera Zoo

IP cameras come in all kinds of shapes, sizes and specifications. Amidst the good, the bad and the ugly, some are designed to sit on desks, others to mount over doorways. Some mount in ceilings, others are wireless, and there are those fitted with infrared LED's to see in the dark. What they all have in common is they can be viewed from anywhere across the internet.

A typical entry level specification would be: Fixed lens of average quality, VGA resolution of 640 x 480 pixel images, fixed position, poor sensitivity in low light, limited bandwidth when streaming, no on-image date and time. A typical high specification device: High quality zoom lens with remote pan and tilt control, high sensitivity in low light, more than one mega-pixel resolution, time stamping and live video streaming with audio.

Wireless Internet Protocol cameras

Many IP cameras are now wireless, which means they have the ability to connect remotely to a network using a wireless access point, in the same way a laptop computer does.

With a range of around 70 meters (200 feet), a Wi-Fi enabled web-camera is a practical alternative to running long cables. However, although wireless when it comes to their network aspect, wireless cameras still need a wired power connection.

PROS: Ideal stand alone solution for a REMOTE weather web-camera.
CONS: Requires a Wi-Fi connection.

Pan and tilt cameras

Some budget IP cameras can be panned around or tilted up and down like a professional CCTV camera. Some models can pan around 340 degrees and tilt up 60 degrees, which is more than enough coverage for scanning the sky for the best weather phenomena. Furthermore, many brands allow control of the web-camera remotely over the internet using an ordinary web browser.

For maximum value, a movable weather web-camera will require a fairly high and uninterrupted point-of-view of the horizon.

A caveat for allowing unrestricted public access to a movable web-camera; the web-camera may be pointed in a direction that was never intended or worse, it could be maliciously directed at the sun.


			A wireless Internet Protocol camera (left) and a conventional USB webcam. Note the different lens diameters. The lens on the IP camera is about 7mm in diameter, whilst the lens on the USB webcam is the tiny red dot in the middle of the lens shade, no more than 1.5mm across! Generally, the wider a lens, the more sensitive a camera will be to low light levels. Also, the image quality in terms of sharpness and colour saturation is improved.

Using analogue video cameras

It is possible to use a conventional analogue NTSC or PAL video camera as a web-camera. The video camera can be anything from a miniature single board spycam, to a full sized camcorder. Video cameras can be connected to a video capture card, a piece of hardware installed inside a computer which captures images off any video source. However, as with USB webcams, for a video camera to broadcast images over the internet, software must be pre-installed on the capture computer and, that computer that must remain switched on throughout the broadcast.

Alternatively, a video camera can be connected to a device called a Video Server. A video server is a stand alone box that operates like a video capture card, converting analogue video into digital images. Images are then either uploaded to a web site (using the FTP protocol) or, served on request to web browsers anywhere on the internet via the video server's built-in web server. Like IP cameras, video servers connect directly to a network and therefore, do not require a dedicated computer to make them work. Typically, video servers produce an image size that is a permutation of 486 by 648 pixels for NTSC video sources and, 768 by 576 pixels for PAL.

PROS: Use cheap and discrete video cameras.
CONS: Video server may not be so easy to obtain.

Designed for the monitoring of CCTV systems over the web, video servers will often have more than one video input; such as this model with four inputs. For weather use, a number of angles can be covered simultaneously; such as the north, south, west and east horizons!


			Digital still cameras A recent development in landscape and weather web-cameras is the use of digital still cameras. These are conventional digital cameras that have been adapted for web use with the addition of custom software. The advantage that digital cameras have over their web-camera counterparts is mega-pixel performance and, significant gains in colour and contrast rendition. However, due to the nature of adapting a specific branded digital still camera plus, the need to install bespoke software on another computer, means for now, adapted digital cameras are only for the most dedicated techie. PROS: Excellent image quality. CONS: Bespoke software and technical support issues.

Streaming versus static image

Most web-cameras can broadcast or stream live video images to any place on the internet. Live means broadcasting images with a refresh rate of anything from a stuttering one frame every five seconds, up to smooth flowing thirty frames per second.

However, streaming live images is bandwidth hungry. Bandwidth represents the maximum number of bytes that can flow along a given network connection. High refresh rates equals many images, equals a high bandwidth overhead. Hence, when streamed across a public network, a broadcast may freeze or fail to load. To achieve smooth streaming often means having a tiny frame with a low refresh rate.

Furthermore, to view a streaming web-camera on a web browser often requires the installation of a browser plug-in. A plug-in is an extra programme that enables viewing of the streamed images inside a standard web browser. Plug-ins are sometimes called Applets, because they are written in a computer language called Java. Although a Java-Applet can run on many different types of computer, this still means that the Java Runtime has to be pre-installed on each computer wishing to view the streamed images. Plug-ins written specifically for PC's running the Windows operating system and are often termed Active-X objects. Both Java-Applets and Active-X plugins have important software security issues when installed across the world wide web. Despite assurances of integrity, many people will refuse to install a plug-in when prompted to do so by their browser.

Live streaming is a must-have for CCTV style monitoring, but for a weather web-camera with a subject that changes slowly over minutes, streaming is unnecessary. A weather web-camera should seek to update a static image every 5,10,15,20 or 30 minutes. Given the speed at which the sky changes, this will be good enough to provide a live view. As a result, there will be no need for anyone to pre-install a plug-in just to view the images, because images are viewed in their standard Jpeg format; just like the picture below.

Noticeable changes to the sky only occur over a few minutes, which makes live streaming unnecessary for a weather web-camera.

However, live streaming might be necessary if you live in Tornado Alley. A very hard camera enclosure will also be needed!

Light sensors

The eye inside the web-camera is either a CCD sensor (charge coupled device) or, more commonly, a MOS sensor (metal oxide semiconductor). Both types of device have a surface layer of light sensitive components which are arranged as tens of thousands of pixels. Each pixel is masked to be sensitive to red, green or blue light. Usually, there is a one to one relationship between the number of pixels on the sensor and the dimensions of the outputed image; the more pixels, the greater the image resolution.

CCD sensors are often found in high quality web-cameras and digital cameras. Not only do they produce high quality images but, they will also produce a useable image at low light levels; CCD based webcams are often adapted for astronomy work.
MOS devices are cheap to manufacture and consume less then one percent of the energy of a CCD. However, they have poor light sensitivity and produce under-saturated and grainy images in dim lighting conditions.

Generally, MOS based web-cameras are cheap, cheerful and made for good light applications; such as a weather web-camera. CCD cameras are expensive and made for specialised surveillance purposes.


			Summary USB Webcams are cheap and easily available, but they require connecting to a computer, can only be five meters from that computer and, the computer must have specialist software and drivers pre-installed. Internet Protocol Web-cameras are an ideal stand alone solution. They connect to the internet and serve images without the need for a computer. Wireless IP cameras have all of the benefits of the above, with the added bonus of no network cabling. Video Servers offer an effective alternative to IP Cameras, as they can use any kind of video camera. Still-digital cameras make very good weather web-cameras but, the technology is immature. Pan and tilt cameras work best with an uninterrupted view. Streaming video is not required for a weather web-camera, except in extreme conditions.