Information

Definitions in security surveillance cameras: standard definition, high definition, full high definition

  Security video surveillance camera, driven by the consumer electronics market, coupled with the CRT TV is changing to LCD and plasma TV screens, HDTV has achieved tremendous success. With the application of HDTV in the field of video surveillance, the concepts of SD, HD and full HD in surveillance basically follow some terms of HDTV. Compared with analog CCTV system, HD means excellent image quality.

  

  Definition SD

  

  The so-called standard definition is a video format with physical resolution below 720p (1280*720). Specifically, it refers to the "standard definition" video format of VCD, DVD and TV programs with resolution of about 400 lines, that is, standard definition. Usually refers to Full D1 (720 *576), or SMPTE 259M standard.

  

  HD

  

  The physical resolution of 720p or more is called high definition. 720p means that the vertical resolution of the video is 720 line-by-line scanning. There are two internationally recognized standards for HD: the vertical resolution of video exceeds 720p or 1080i, and the aspect ratio of video is 16:9.

  

  The division of "HD" and "Standard Definition" comes first from the visual effects. Due to the difference of image quality and bandwidth of channel transmission, digital TV signals are divided into HDTV (High Definition Television), SDTV (Standard Definition Television) and LDTV (General Definition Television). In terms of visual effects, HDTV has the highest specifications. Its image quality can reach or close to the level of 35mm wide screen movies. It requires the horizontal resolution of video content and display equipment to reach more than 1000 lines, and the highest resolution can reach 1920 x 1080. From the perspective of picture quality, because the resolution of HD is basically four times that of traditional analog TV, the picture clarity and color restoration are much better than traditional TV. The 16:9 broadscreen display also brings broader visual enjoyment.

  

  Due to cost constraints, HD has not been effectively applied in the video surveillance industry. With the development of chip technology and compression algorithm, high-definition video surveillance products are gradually emerging. Now D1 standard video compression format has been formally written into the national standard of Digital Hard Disk Video Recording System (DVR). As far as the video surveillance industry is concerned, there are already commercial high definition network cameras (HD IP Camera) and video servers based on standard H.264 in the market. The definition can usually reach 720P, 1080P or even higher resolution formats.

  

  Full HD FULL HD

  

  The so-called Full High Definition (FULL HD) refers to the physical resolution up to 1920 *1080 display (including 1080i and 1080P), where I (interlace) refers to interlace scanning; P (Progressive) refers to line-by-line scanning, which has a great difference in the accuracy of the picture, 1080P quality is better than 1080i. 720 is called standard HD correspondingly. Obviously, due to the more abundant data information in the transmission process, 1080P has more advantages in resolution, especially in large screen TV, 1080P can ensure a clearer picture quality. Full HD products are usually used in some important occasions in monitoring system due to cost and other reasons.

  General Standard of HDTV and HD Monitoring System

  

  The resolution of HDTV is up to 5 times that of standard analog TV. HDTV also has better color fidelity and 16:9 format. The two most important HDTV standards defined by SMPTE are SMPTE 296M and SMPTE 274M.

  

  SMPTE 296M (HDTV 720P) defines resolution of 1280 *720 pixels, high fidelity color in 16:9 format and sequential scanning frequency of 25/30 Hertz (Hz), i.e. 25-30 frames per second. It also supports 50/60 Hz scanning frequency (50/60 frames per second) depending on the country.

  

  SMPTE 274M (HDTV 1080) defines a resolution of 1920 *1080 pixels, high fidelity color in 16:9 format, using 25/30 Hertz (Hz) and 50/60 Hz alternating or sequential scanning frequencies.

  

  SMPTE-compliant cameras indicate compliance with HDTV quality and should provide all HDTV resolution, color fidelity and frame rate advantages.

  

  HDTV is based on square pixels, similar to computer screen, so HDTV video from network video products can be displayed on both HDTV screen and standard computer monitor. Using sequential scanning of HDTV video, when the video will be processed by a computer or displayed on a computer screen, there is no need to apply conversion or de-interleaving technology.