Since HD surveillance is not yet fully popular, the concept of high-definition in the current market is still vague or even erroneous. Therefore, before elaborating the relationship between high-definition and NVR, we need to first understand some of the core concepts of high-definition surveillance:
1) The front end of HD monitoring must be an HD IP camera
Traditional SD monitoring can be divided into analog, digital, and network types. The front end of these monitoring systems can use analog cameras, network cameras, video encoders, analog cameras, and other types, but in HD monitoring, the front end must be HD IP camera.
First, the uncompressed high-definition video signal after the acquisition has both analog and digital transmission methods. No matter whether it is analog or digital transmission, the transmission cost of uncompressed high-definition video signals will be much higher than the previous analog SD video. The signal, therefore, can see that the transmission of high-definition video signals cannot continue to use the transmission methods of SDTV systems in the past, but can only compress and encode the video and transmit it through the IP network, and adopt this transmission method and the transmission of the SD system. The difference in cost is minimal.
Secondly, because of the high cost performance of CMOS high-definition video sensors, the efficiency and cost of directly using high-definition network cameras for front-end processing are more advantageous than those of high-definition video encoders and high-definition cameras.
2) HDTV HD standard system is the mainstream
After the video resolution of the monitoring device reaches megapixels or 720p, it can be called HD, and in fact, there is still a big difference between megapixel and 720p.
720p is derived from the HDTV standard developed by the Society of Motion Picture and Television Engineers (SMPTE). According to the standard, there are three main formats that truly meet HD video: 720p (1280*720) resolution, 1080i (1920*1080) resolution, and 1080p (1920*1080) resolution. This high-definition video standard originally used in the broadcasting and TV industry has also been commonly adopted by the video surveillance industry as a recognized technical standard.
The megapixel is not a recognized standard, but it actually refers to the number of image sensor elements of the network camera. When a high-definition IP camera has more than megapixel performance, it is still not known what the frame rate of this camera is, how the video aspect ratio is, whether it is interlaced or progressive, how the color fidelity is, and so on. It is also the main indicator of the performance of a high-definition IP camera. Therefore, as an industry standard, it is clear that the HDTV standard is more practical.
3) H.264 will dominate the video coding technology
HD video camera video coding standards are mainly MJPEG and H.264 two. MJPEG (MotionJPEG) is a dynamic image compression technology developed on the basis of JPEG. Although it has certain advantages, its defects are also very obvious, including serious drop frame phenomenon, poor real-time performance, low compression efficiency, and large transmission bandwidth and storage space. .
H.264 is a new-generation video coding standard developed by the joint video work group JVT jointly established by ITU-T and ISO. It not only saves more than 80% of the bit rate of MJPEG, but also has better support for network transmission. As a result, broadcast-quality HD video resolutions of 720p and 1080i/p can be achieved at lower bandwidths.
As mentioned earlier, although NVR has many innovative advantages, the true popularity still needs a core competitive feature to pull, and the high resolution, high fluency, and large-screen and wide-screen display based on the above high-definition technology The ability to dramatically improve the ease of use of the monitoring system and the user's image browsing experience, etc., coincides with the requirements of the NVR's core competencies. At the same time, since the basic premise of high-definition monitoring must be networked, the combination of high-definition and NVR is a matter of course.
Finally, coupled with the excellent quality of NVR itself, including the integrated functions we already know and recognize, including access management, video storage, and decoding, we believe that in the era of high-definition surveillance, NVRs will be able to face unprecedented opportunities for development. .
Perforated Metal Mesh, (also named Perforated Sheet, Perforated Metal) refers to the metal sheet products with various different holes on the surface. There are many kinds of punching wire mesh products. Different shapes, different sizes of holes, can adapt to different needs.
Material: Stainless steel, low carbon steel plate, galvanized, PVC, cold rolled coil, etc.
The types: pattern perforated sheet, forming perforated plate, extra thick punching net, ultra thin punching mesh, micro porous perforated sheet metal, wire cutting punching net, Laser punching net, etc.
Shape of Hole: Rectangular hole, square hole, diamond hole, round hole, hexagonal hole, cross hole, triangle hole, long round hole, long waist hole, plum blossom hole, fish scale hole, pattern hole, five pointed hole, irregular hole, bulge hole, etc.
Use: Sound-absorbing materials for ceilings and wall of buildings; Exquisite decorative board for building staircase, balcony, environmental protection desk and chair; Machinery and equipment protection cover, grille gorgeous, food, feed, mine mill sieve, sieve screen, I-beam, stainless steel kitchen equipment, food cover, blue fruit and other kitchen utensils, and shopping malls with shelves, exhibition decoration, ventilation network for grain depot, football turf seepage water filter and so on.
Size: 1.Thickness of coil: 0.2mm-1mm; Length: 20m
2. Diameter of hole: 1.5mm-10mm
3. Thickness of plate: 0.2mm-20mm;Width*Length≤1.5m*5m
4. Diameter of hole: 0.5mm-200mm
Hole diameter:
Generally speaking, the aperture size is approximately greater than or equal to the thickness of the plate, which is in accordance with the principle of minimum pore diameter. The closer the diameter of the hole to the thickness of the sheet, the greater the difficulty of processing and the higher the processing fee.. In some raw materials, the hole size can be less than the thickness of the plate.
Pitch
The pitch is
the distance between the middle of a hole and the other one, the nearest hole
in it. The middle distance is a way to represent the interval between holes,
and the other is the rate of opening. The essential meaning of the two
representations is the same. So you just need to identify one of them.
Arrangement of holes:
(detailed picture explanation)
We can make all kinds of difficult passes and
patterns. Although special requirements for pass and pattern require a
specified processing fee, the quotation for the usual pass is quite reasonable.
(1) 60 degree staggered row
60 degree staggered row is one of the most popular choices with its natural high strength and wide
aperture ratio and attractive appearance
(2) 45 degree staggered row
Compared
with the former, the 45 degree plum blossom provides another choice for people.
(3) Straight Row
Another kind of round hole placement is straight row, straight row can also have a variety of holes and opening rate, but it is the hole in the series of the worst compressive strength.
Structure:
Perforated Metal Mesh
Perforated Metal Mesh,Perforated Metal Aluminum Mesh,Stretched Perforated Metal Mesh,Stainless Steel Perforated Metal Mesh
Anping Xinzheng Metal Wire Mesh Co., Ltd , http://www.sievingmesh.com