Recently the biggest issue in CCTV market can be said to be the high resolution application of HD or MegaPixel class more than anything else. The change of resolution from the existing SD(720x486:NTSC) class to HD(1920x1080:HD1080p) class requires a change in the whole system, not a picture quality enhancement of camera simply. A SD class(NTSC/PAL) image was not enough to meet the market requirement of the times, high definition and high visibility, in the HDTV era due to a limitation in resolution. The market requirement for high definition started to be applied to the CCTV market in a MegaPixel IP camera type along with the development of a HD class sensor at a reasonable price, and recently HD-SDI transmission technology was grafted on the CCTV market, starting to be introduced as a product group of HD-CCTV.
A HD image system can be configured by introducing a HD-SDI transmission method that is used in the broadcasting market. This can realize a security system by introducing a verified transmission method.
In here, we want to define a CCTV to transmit a SD class image through a coaxial cable as a SD-CCTV and a CCTV to transmit a HD class image through a coaxial cable using a HD-SDI transmission method as a HD-CCTV. This is because the HD-SDI transmission method was developed as the most suitable transmission method to transmit a HD class image without deterioration in picture quality, being used as a standard transmission method between broadcasting systems for a HDTV. Now, the high definition video security market is expected to develop into a new shape through competition and fusion between the HD-CCTV market and the IP market.
HD-SDI is a standard specification to transmit an image between HD class broadcasting systems. HD-SDI is an abbreviation of High Definition Serial Digital Interface, which means a method to convert a digital image signal into a serial signal and transmit it through a coaxial cable without compressing it. HD-SDI was standardized by SMPTE, which describes all the contents of electric interfaces, data formats, auxiliary data and video formats.
The feature of HD-SDI transmission method is that it can transmit an image signal without deterioration in picture quality as it is within a distance where data are not lost because it transmits an image as a digital signal. It can transmit audio and control signals as well as images, and it seems that it will be able to supply power in the future.
A HD-SDI transmission method is basically different from a SD class transmission method. As shown in the table below, there is a difference that their transmission methods are a digital method and an analog method although they use the same coaxial cable externally. In addition, the HD-SDI transmission method is one of the SDI transmission methods, which can send up to 1080p30. This is defined in SMPTE 292M, which uses 1.485 Gb/s transmission data quantity and 750MHz transmission frequency.
- HD-SDI : A technology to transmit a HD image digitally through a coaxial cable without compression
- HD-CCTV : A CCTV system realized with a HD image by using a HD_SDI transmission method
- HDcctv : A HD-CCTV guaranteeing the specification and performance defined by the HDcctv alliance
The figure below is an example of using a HD-SDI transmission method, showing that various types of cameras are connected with a HD-SDI DVR using a HD-SDI transmission technology to realize a system. In here, HD-SDI cameras, repeaters, DVRs, etc. were used. A repeater can be used in the middle of a line to extend the transmission distance of a HD-SDI signal. The existing monitoring camera can change a signal into a SDI signal through a converter.
Comparison of features of a HD-CCTV system
The following summarizes the property difference between a HD-CCTV system, SD-CCTV and IP based system as a table. Taking a look at one, the feature of a HD-CCTV shows that a camera image can be recorded without being affected by network errors because the most important part of transmitting and saving a camera image uses a coaxial cable. This is just one of the key factors in a security system.
The transmission distance of an existing SD-CCTV is 300m or more when using a coaxial cable. The transmission distance of a HD-SDI is about 150m~200m when using a coaxial cable exclusively for a HD-SDI. Of course, there may be a little difference depending on quality of coaxial cables. Even using an existing coaxial cable can transmit an image at least 100m. For your reference, the transmission distance of a UTP cable(CAT5,6) for network communication is 100m. Accordingly, the transmission distance may not be a weak point. In addition, using a commercialized HD-SDI repeater or optical transmission converter can extend the transmission distance as much as one likes.
A HD-SDI monitoring camera can be networked through a DVR or video server. There is no problem in integration through a network. Being an issue recently, a smart phone can monitor a HD image. This is because a service can be provided through a DVR. It seems that network monitoring is possible without additional equipment because the connection of a camera and a storage device is essential in a security market.
HD has a 6 times bigger than SD resolution physically, but considering the aspect that picture quality is deteriorated through analog transmission by a SD-CCTV and stationary screens are deteriorated due to interlace transmission(composed of a field of image frame photographed at two different times), the picture quality difference between a SD class and a HD class exceeds the 6 times difference by far. In addition, realistically most of the monitoring equipment(HDTV, LCD monitor, etc.) has a 1920x1080 resolution. The HDTV broadcasting also uses a 1920x1080 screen size. You can use a piece of monitoring equipment of HD resolution at the most competitive price. Now, considering the reality that HDTVs are supplied in a full scale just worldwide, a Full HD 1080p resolution is expected to become the most competitive resolution for a considerable period.
The request for a HD-CCTV by the users already accustomed to high picture quality in a HDTV is being received as a very natural thing. There is still a little burden in prices, but it is expected to approach the customer required level in terms of time and price in a not so long time.
The HD-CCTV system introduced for the first time in 2009 started to be released in a full scale from early this year, and is expected to enter a full-scale growth period over 2012 through 2015. It seems that facilities will be changed into a HD-CCTV at most sites requiring a high resolution such as important facilities, banking sectors, etc. during this period. More than anything else, this is because the operation of small scale systems is facilitate and the composition of large scale systems through a network is enabled due to the easy installation and control of a HD-CCTV product with an experience in designing, installing and controlling a SD-CCTV system used so far. As an example, its installation at a place requiring high picture quality such as a highway control system, casino, bank, etc. is being discussed in a full scale. As one naturally purchases a HDTV if it purchases an new TV, it is expected that an era in which the installation of a CCTV system just means the installation of a HD-CCTV system. Now the era of a HD-CCTV is approaching to our eyes.
The following figure shows data to forecast the sales quantity of HD-CCTV systems. These are the data forecasted by HDcctv Alliance, which can forecast the remarkable development of a HD-CCTV market for the future 5 years.