DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN

To copy the eye - a new concept of camera.

A camera lens - the assembly of precision optical lenses and the system of their control - represent a significant cost in manufacturing CCTV, video and still cameras.
In search for a cheaper method of manufacturing the lens and cooperating image sensor, a group of American scientists tried to imitate the construction of the eye.
In the simplest terms, the eye is made up of the eye lens and a light-sensitive panel of cells (retina). The eye lens has all the disadvantages of a simple lens (spherical and chromatic aberration, curvature of the field of the image). They are practically eliminated by the "software" which is the processing done by the brain. The curvature of the field of the image is compensated by the arrangement of photosensitive elements on the surface of semicircular shape.

Schematic diagram of the eye

Researchers from Northwestern Illinois University hit on an idea to put an array of photosensitive elements on a flexible membrane with changeable shape. The radius of curvature is adjusted by changing the pressure of the fluid filling the tank located under the membrane. The result of combining the lens with the array on a similar principle as the operation of human eye (variable radius of curvature) is the development of camera with varifocal lens and good image quality. The effect of the interaction between the lens and the sensor array is a very wide viewing angle without distortion that is normally caused by simple lens and planar array.

Simple optical lens, image senor on membrane, and hydraulic control of the zoom - the new concept of camera

The camera with such a lens and image sensor can be very small, but the potential of the device is very high, especially taking into account the zoom mechanism.
The biggest challenge for the development of this solution is the resolution of the array. The first prototype employed array consisting of only about 300 pixels, which falls far short of the requirements for cameras. So we'll have to wait some time before the solution is sufficiently mature for implementation in real cameras.

Jordan - antenna landscapes.

Multifunctional roofs in Jordan

Amplification of digital and analog TV signals.

The signal levels of digital terrestrial television are typically lower by 10-20 dB compared with analog signals. This fact is of great importance to the work of broadband amplifiers.

When a broadband amplifier gets at least two carriers, it generates a number of intermodulation products, in addition to the desired signals. There is a significant risk that the intermodulation products will interfere with channels occupied by digital multiplexes. Given the much lower signal levels of the digital channels, the effect of using the amplifier can be a complete lack of digital television.

These considerations lead to the following conclusions concerning the most effective amplification of analog and DVB-T signals:

All the above-mentioned requirements are fully met by the masthead antenna amplifiers of Terra ABx series.
Additionally, thanks to universal power supply (5 VDC or 12 VDC) it is possible to use different power sources, including the 5 VDC voltage available in the antenna inputs of DVB-T receivers. The parameters of the preamplifiers are shown in the table below:

New firmware for Hikvision-Ultimax DVRs.

The new version of the software was released in January 2011. Although the software designed for Hikvision-Ultimax DVRs of 3XX and 81XX series is updated on a regular basis, the latest version introduces essential changes.

All the DVRs can now be managed locally by multiple users with granted privileges for making changes in the system. It significantly increases the functionality of the devices, especially when handling larger networks controlled by staff with different access privileges.

The new firmware also introduces support for network-attached storage. This way the surveillance data is stored on a remote server, being protected in the case of theft, damage to the DVR etc.

The most important change brought by the firmware is optimization of recording speed the 73XX series.
The DS-7308HI-S M74080 model, aside from the standard configurations, can now also record (in one channel) images with 4CIF resolution (704x576) at frame rate of 25 fps, whereas the rest of channels is capable of recording (at the same rate) CIF images.
The DS-7316HI-S M74160 model allows to record 4CIF images at frame rate increased to 6 fps (in each channel), or 4CIF images at 25 fps in two channels, when the rest of the channels records CIF images (also at 25 fps).

The emergence of the new version of the software demonstrates a high potential and excellent performance of the equipment, which, given the nature of the systems, is of great importance.

Megapixel lenses from Tokina and UltiEye.

One-megapixel camera (1Mpx - 1,000,000 pixels) provides over twice the pixels than standard PAL camera (704 x 576 = 405 504 pixels). 5 Mpx cameras offer resolution of 2592 x 1944 pixels (12.5 times more pixels than PAL and 2.5 times more than HDTV images).
So high resolutions of the sensors require using adequate lenses. Low-quality lenses would spoil the resultant images.
Megapixel cameras have to be equipped with specially marked "megapixel" lenses. These high quality lenses exhibit substantially reduced geometric distortions and lower deformation of light waves passing through their optical lenses. The deformation is described by MTF parameter - Modulation Transfer Function. This parameter is essential for sharpness of the images and identification capability of megapixel CCTV systems.
A measure of lens resolution is the number of line pairs that can be distinguished in one millimeter. This parameter is closely related to the ability of the lens to provide image detail. The lenses for VGA cameras feature about 30 lp/mm, whereas megapixel lenses should guarantee at least 60 lp/mm.
Megapixel lenses should also be applied to modern analog cameras with resolution of 976x582 pixels. An example of such a camera is SN-BXC5930CDN M11209.

Tokina megapixel lenses

UltiEye megapixel lenses

Day/night megapixel camera with SD slot - Pixord P600E.

If a monitoring system consists of 1-4 cameras, the costs of archiving the video data on a server are relatively high compared to the value of the entire system.
A good solution for such cases is application of Pixord P600E K1532 camera(s). Its SD slot allows to insert SD/SDHC card with capacity up to 32 GB, which would be sufficient for continuous recording of video data throughout 3 days and nights (with full resolution of 2 Mpx). The period can be extended many times when using motion detection or schedule recording - the useful functions that have been implemented in this model. After detection of movement, the camera can send e-mail notifications with still image. The whole footage recorded on the SD card can be played back remotely via the Internet.
Pixord P600E K1532 camera also enables bi-directional audio transmission (due to built-in microphone and speaker connector).

Online video from IP 2.0 Mpix H.264 PoE camera Pixord P-600E - a vista of Wawel Hill in Krakow.

Rear view of the PIXORD P600E K1532 camera (visible SD slot)

Installation of a hard drive and a DVD writer in Trend DVRs.

Trend DVRs are popular, high quality digital video recorders designed for long-term operation in CCTV systems without the hassle of maintenance.
You are welcome to watch the movies that illustrate how to mount the hard disk and DVD writer in the DVRs.

Wireless video transmission from megapixel cameras.

The ideal devices for video transmission from the cameras are ULTIAIR access points, allowing transfer speeds up to 54 Mbps.

A city surveillance system based on wireless transmission using ULTIAIR equipment

Both for the transmission of video streams and PTZ commands there can be used access points integrated with antennas, powered via PoE. The base station cooperating with multiple access points should employ sector antennas which will allow for more manageable sections.

We have written about:

AverMedia hybrid DVRs in a luxury office building. Built in the late twentieth century, Rahimtulla Tower is one of the tallest buildings in Upper Hill, a business district of Nairobi, Kenya. It is the home of many multinational corporations, with 22 floors and two parking levels, every day visited by thousands of employees and customers...

Mobile video monitoring with an Android cell phone

Video transmission over longer distances using twisted pair cable. Video signal transmission via twisted-pair cable is justified not only economically (UTP cable is much cheaper than coaxial cable and has four twisted pairs), but also technically, due to elimination of interferences and possibility of using very long transmission lines , up to 2400 m. The general name of the device that matches (transforms) the 75 ohm impedance of an unbalanced source to the impedance of a balanced line formed e.g. by a pair of the UTP cable (and vice versa) is balun (balanced/unbalanced).
Transmitting a single video signal over a distance up to 400 m we can use one of the simple sets of passive baluns of Etrix series...

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