IP CAMERA LEARNING & RESOURCE CENTER

P-iris is an automatic iris control system developed by Axis Communications, designed to give precise control over the iris opening using a stepper-motor driven iris and specialized software. The P-iris system has been developed to make improvements over the traditional auto-iris by giving better control over the aperture.

In bright conditions an auto-iris lens may be subject to blurring caused by diffraction. This is when the surrounding light levels cause the iris to close too much. This is even more noticable in megapixel cameras where the pixel size in the image sensor is a lot smaller than conventional standard definition cameras.

This has led to Axis developing an iris system where the user has greater control over the aperture and by doing so has provided greater image quality with higher contrast, increased clarity, higher resolution and better depth of field control.

P-iris is expected to replace the DC-iris as the standard method of iris control in fixed Axis network cameras.

Image on left shows traditional lens, image on right shows the new P-iris lens demonstrating better depth of field control

Another method of accessing an IP camera is by way of a guest user account.

This is a function found in almost every IP camera which allows you to login and view the live images from your camera without having to enter a username or password.

The benefit of guest user access is that you can open an IP camera to visitors.  This allows you to embed the live image in a web page so you can use an IP camera as a streaming webcam attraction.

Almost every IP camera we deal with on a day-to-day basis has some form of multi-level user authentication but what do we mean by this?

User Authentication indicates that before the user can access the live images from an IP camera he/she must first input a username and password to authenticate themselves as a valid user.

‘Multi-level’ authentication implies different levels of permissions for different users.  Each camera type handles user levels differently and some models allow for more customisation than others but typically you can set up users as administrators, operators or viewers.

Administrator

An administrator would have full access to the camera in the same way the owner does.  This allows them to view the live images, control the camera and adjust image settings and access the camera’s setup pages where they would have access to the camera’s full configuration including network settings.

Operator

An operator would be able to view and control the camera and adjust image settings etc. but would not have access to any of the camera’s setup pages.  This allows someone to view and control a PTZ camera but keeps all the critical settings of the camera safe such as the network settings.

Viewer

Finally a viewer would be someone whom, after logging in, would have permission to view the image but would not be able to do anything else.

Please consult your camera’s documentation for further instructions.

H.264 (or MPEG-4 part 10) is an emerging standard in IP video and IP CCTV.  It is a method of video compression which can dramatically reduce the bit-rate of live streaming video without any reduction of image quality.

Side-by-side, the size of the data streaming from a camera using H.264 will be up to 80% less than MJPEG and up to 30-50% less than MPEG-4. This means that bandwidth load across the network is significantly reduced when using H.264 compression and storage costs will be lower when recording CCTV footage.

The downside of H.264 compression has been the increased hardware costs due to greater amounts of processing required by the camera. This has made the technology available in only the very high-end network cameras so far, but this is changing.  With the recent launch of the Axis M10 series we are now seeing the introduction of H.264 in entry-level IP cameras and we think that H.264 will fast become the standard video compression format of choice for all network cameras in the years ahead.

The Hyper Text Transfer Protocol is the protocol used by network devices such as IP cameras and PCs for transmitting information across the internet. The Protocol was designed by CERN in Switzerland in the late 1980s as an easy way of transferring text documents. The project grew rapidly and now almost every website in the world uses it.

IP cameras usually have a built in HTTP server to ease configuration and viewing. This is what you see when you log into your camera. These usually use port 80, although most cameras allow this to be changed if necessary.

A CMOS sensor, when applied to IP surveillance cameras, is a device which converts light energy into electrical voltages which can be read by an IP camera and translated into images. In a similar manor to CCD sensors, CMOS sensors are made up of thousands or millions of light-reactive cells. Each reacts to a component of light; red, green or blue. The amount of light on each cell is translated into a voltage which is read by the camera and translated into data. This is then compressed and sent across the network to the viewing computer which arranges the data back in its original colour and position providing a picture.

CMOS sensors are a lot newer than CCD sensors and thus the technology is improving all the time. CMOS sensors also require a lot less power than a comparable CCD sensor. CCD sensors tend to offer a higher quality image than a comparable CMOS sensor, although CMOS image quality is progressing as time passes.

The Dynamic Host Control Protocol is used to set up network devices with a useable IP address with little-to-no manual intervention. The protocol, usually used by routers or servers, uses a “pool” of usable IP addresses. When a new device connects to the network with DHCP enabled, it makes a request to the router or server for an IP address. The assigning device will supply an address to the device and will remove the address from its pool. This means that should another device connect there is no possibility of it receiving the same IP address and causing a conflict.

A Charge Coupled Device (CCD) is a type of image sensor and is basically the eye of your IP security camera. Is it a small, light-sensitive integrated circuit which translates the light which hits it into a digital electrical signal.

On the CCD there are thousands or even millions of tiny receptive cells. These cells react to the red, green or blue light components and records each as a voltage. The voltage is then read by the camera, compressed and then sent along the network.

CCD sensors are usually measured in physical dimensions. In IP CCTV cameras these are usually 1/4, 1/3 or 1/2 an inch. Larger sensors tend to give a better picture as they have a larger surface area to catch more light.

Analogue, when applied to CCTV, refers to security cameras which output video signals in a wave form, rather than a series of 1s and 0s. Older CCTV cameras tend to use this as their primary form of video output. Some newer IP cameras offer this as a secondary output so that older monitoring equipment can be used, easing migration from analogue to digital IP systems.

MJPEG is short for Motion-JPEG which is a means of storing video footage from IP cameras and digital camcorders.

An MJPEG Movie consists of many JPEG images, one after another. Since JPEG is a compressed format, so too is MJPEG, providing a low file size when compared to image dimensions. Each frame of an MJPEG movie has no reference to the next, so inter-frame compression is not used, making MJPEG movies larger than similar MPEG movies. However, since there is no inter-frame compression the file size of an MJPEG movie will not change dependant on the complexity of the images used. This means the file size is a lot easier to estimate when looking at recording solutions.

MJPEG, being composed entirely of JPEG images, is a video-only format.  Should you require audio recording you may wish to use another codec such as MPEG or H.264.