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

Artificial intelligence improves the quality of photos.

Google has introduced a new technique for increasing image detail, RAISR. The Rapid and Accurate Image Super-Resolution uses machine learning to improve the quality and detail of images. The whole process is up to 100 times faster than current techniques and can be performed on smartphones in real time. The improvements result not only in more detailed images, but also eliminate various undesirable phenomena, such as aliasing artifacts.

Comparison of the effects of bicubic (picture in the middle) and RAISR (on the right) upscaling
of the original picture (on the left) - [source: research.googleblog.com]

Currently, the most commonly used linear algorithms for increasing image detail/resolution insert extra pixels with colors based on the analysis of the adjacent pixels. Such algorithms bring quite miserable effects - the output images become blurred. Google uses a self-learning algorithm. The learning process involves comparing pairs of the same images with low and high resolution. "RAISR filters are trained according to edge features found in small patches of images, - brightness/color gradients, flat/textured regions, etc. - characterized by direction (the angle of an edge), strength (sharp edges have a greater strength) and coherence (a measure of how directional the edge is)." The analysis of 10,000 pairs of images takes one hour. After the creation of such a database, the algorithm can convert any image increasing its resolution in real time.

RAISR in action - enlarge the picture to clearly notice the difference

Elimination of aliasing
(source: research.googleblog.com)

Google has developed image processing technique that can find very wide application. There are a lot of images that need some improvement. Thanks to operation in real time, the method can be also used in smartphones. Due to various constraints, the downloaded images are often available in unsatisfactory quality/resolution, and could be processed "on the fly" to enhance their parameters. The company plans to refine the algorithm so that it could instantly improve the quality of any portion of the image the user wants to enlarge.

In this case, the learning method can lead to some irregularities. For example, filters developed on the basis of a set of human faces may be irrelevant to a specific face. This risk could be minimized by limiting the zoom ratio. How will work RAISR in practice? We'll see.

Directional combo DVB-T antennas with changeable polarization.

The Yagi-Uda or Yagi antenna is one of the most popular antenna designs, due to a comparatively simple construction and high gain. Yagi-Uda antennas can operate in the HF to UHF bands (3 MHz to 3 GHz), but often within a limited bandwidth around the center frequency. In the case of DVB-T bands, the parameters are chosen so as to maintain the balance between the range of channels that can be received and the average gain within the frequency band. Another aspect is the polarization of the transmitted signals. The antenna elements (directors, dipole, reflector) have to operate in accordance with the polarization of the signals, otherwise the gain of the antenna would disappear. Usually, all transmitters in an area operate with the same polarization in one band (UHF or VHF), but the polarization of the broadcasts in the UHF and VHF bands can be different. Such a situation is in Poland, where the new MUX-8 is transmitted in the VHF band with vertical or horizontal polarization, depending on the area. The appropriate polarization of the receiving antenna is essential for the proper reception of the DVB-T broadcasts.

DIPOL is the first company that manufactures Professional VHF and UHF DVB-T Antenna Sets (H/V). Thanks to a universal construction, the VHF and UHF antenna segments can be independently set to the vertical (V) or horizontal (H) polarization of the received signals. We offer two versions specially designed for receiving DVB-T broadcasts with different polarizations in VHF and UHF bands: DIPOL 28/5-12/21-60 A2810 and DIPOL 28/5-12/21-60 DVB-T with LNA-177 amplifier, A2850. The both antenna sets are equipped with diplexers combining signals from the VHF and UHF bands.

View of the professional VHF and UHF DVB-T antenna set
(both segments operating with horizontal polarization)

View of the professional VHF and UHF DVB-T antenna set
(VHF segment operating with vertical and UHF with horizontal polarization)
In this configuration, the U-bolt has to be mounted at the end of the antenna carrier

The DIPOL 28/5-12/21-60 A2810 and A2850 professional DVB-T antenna sets have been designed for reception of TV broadcasts in VHF (174-230 MHz) and UHF (470-790 MHz) bands. They provide an effective solution for the reception of DVB-T broadcasts with various combinations of polarizations in the VHF and UHF bands.

How to improve cellular connectivity?

Mobile phone conversations in buildings are often difficult to carry on, if not impossible. This is due to the signal attenuation through walls, window panes, ceilings (underground). The problems occur in stores, tunnels, underground car parks, petrol stations, airport halls, hotels. A similar situation can be found in buildings located on the border range of base stations (recreational areas, mountains etc).

Signal GSM-305 A6765 repeater amplifies GSM signals inside buildings. The device is ideal for locations where the range of a cellular network allows for use of mobile phones out of buildings, but is insufficient for indoor operation. The device has to be connected with an outdoor antenna (e.g. A741030) directed towards the base station, and with indoor antenna(s), e.g. A741001.

When deploying indoor antennas, one should pay attention to the total area and the number of rooms that are to be covered by the amplified signals. It is important to ensure maximum isolation between the outdoor and indoor antennas (usually by installing the outdoor antenna over a large distance from them, somewhere on the roof). Typically, the installation of the indoor antennas should be started from the lowest level since it is often possible to cover two floors with antenna/s located on one floor. We offer three antennas from TRANS-DATA series, specially designed for cellular amplifiers: A741001 (fixing to plasterboard or other suspended ceilings), A741002 (fixing to solid ceilings with the use of expansion bolts) and A741020 (fixing to walls).

Ultimode quick assembly connectors.

ULTIMODE ILB-2SM-A L7102 duplex cable composed of two single-mode G.657A1 fibers is one of the most popular FTTH cables on the market. The popularity of the indoor cable is the result of low price, high mechanical resistance, and a special construction with rectangular cross-section of the jacket plus built-in FRP reinforcing rods naturally limiting the bending capability in one plane to a safe bending radius range.

Quick Assembly Connector ULTIMODE FAST-02SC L5711 on Ultimode L7102 cable

The cable can be terminated with pigtails connected via mechanical splices (e.g. ULTIMODE L5550), fusion splices (made e.g. with EasySplicer L5810), or using quick assembly connectors ULTIMODE L5711 or L5712. The latter option is possible thanks to small dimensions of the cable, ideally suited to the size of the connectors. The convenient and cheap solution can be recommended for LAN and CCTV systems based on optical fibers. It can also be used in the interim period during the installation process of FTTH systems, before performing final fusion splices.

Cameras operating in four video standards, for any analog CCTV system.

n-cam and v-cam cameras are universal devices for applications in CCTV systems based on various types of DVRs. The video system is selected by long pressing (5 s) the thumb stick to the right (HD-TVI), left (CVBS), up (AHD), or down (HD-CVI). The stick is placed in the small box on the camera cable.

View of the control box on the connection cables of n-cam and v-cam cameras.
With the thumb stick the user can select the required video system.

Corridor mode in Hikvision cameras.

Hikvision cameras have "Rotate Mode" which is particularly useful for observing areas such as corridors or hallways, characterized by a large disparity in size between the depth (visible by a camera as the height) and width of the scene. In this mode, one camera is capable of capturing a "deep" or "vertically-shaped" scene from a comparatively short distance, cutting out the inessential information from the both sides in the immediate vicinity of the camera. For this mode it is necessary to turn the camera by 90° with respect to the normal position, which changes the aspect ratio of the image from e.g. 16:9 to 9:16.

Checking the continuity of fiber optic cable using a reflectometer. The stage of laying cables is always one of the most time-consuming, and thus costly phases of each installation. In the case of fiber optic cables, they can be easily damaged by incorrect transport or storage (microbending), so it is particularly important to check them before installation in cable ducts, jointing chambers, walls, etc... >>>more

Verification of fiber optic cable on a drum with the use of Grandway FHO3000-D26 L5828
optical time-domain reflectometer

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