In the modern production process,industrial automation in the production has adopted the TV monitoring system ,such as metallurgy, coal, petrochemical, explosion-proof, industrial park, etc.It has each difference in the format description of resolution used in the industrial video monitoring system .
Currently ，resolutions mainly used in industrial inspection are QCIF (176 x 144), CIF (352 x 288), HALF D1 (704 x 288), D1 (704 x 576) and so on .CIF is the mainstream video resolution, most products using the CIF resolution There are four main reasons that the market accept CIF resolution at present :
(1)At present the digital industrial detection can not have too high video streaming requirements;
(2) Video transmission bandwidth is also limited;
(3)Using the HALF D1, D1 resolution can improve the clarity and meet the requirements of high quality, but at the cost of high stream.At present, there is a lot D1 products,but in a small market share;
(4)Using the CIF resolution, the general user can accept the SNR in 32 db or more, but it is not the ideal video image quality.The insider is trying to use HALF D1 to seek the balance between CIF and D1.However, as the single disk capacity reach up to 750 GB or 1000 GB, and the majority of domestic DVR can connect the 8 piece of 1000 GB hard disk , so now the D1 will gradually become the mainstream .
What is DCIF resolution?
A more effective industrial monitoring resolution (DCIF) video encode has been found after research,which is 528×384 pixels.The origin of video image's resolution is the odd and even two HALF D1, via an interlaced transformation, to form a D1 (720 * 576),D1 as the border processing, become 4 CIF (704 x 576), 4 CIF by horizontal 3/4 ,vertical 2/3 narrowed, convert 384.528 x 528 x 528 pixels which is the double of the CIF pixels ,In order to distinguish with 2CIF , we call it DOUBLE CIF, DCIF for short.Obviously,DCIF is more balance than HALF D1 in horizontal and vertical directions .
Reasons for selecting the DCIF resolution:
Digital video monitoring industry puts forward two requirements to digital industrial products: Firstly it requires the low data volume and guarantee system can record for a long time and stable for the real-time network transmission;Secondly ,it requires the higher image resolution when it playback and meet the requirement for details.And DCIF resolution in the current hardware and software platform which can be good to satisfy for the above of two requirements.HALF D1 resolution has been used by the part of the product, which is used to solve the CIF resolution high enough and D1 high storage capacity and the disadvantage of high cost .But as it only improve the horizontal resolution , image quality improvement is not specially obvious, but stream (Data Rate) increase a lot.After testing a large number of video signal and based on the current video compression algorithms,on inadequate clarity of CIF and disadvantage of high storage &high price of D1 ,DCIF resolution better works them out than HALF D 1 using to solve the CIF and 4 CIF, especially between 512 KBPS bit rate, it can obtain the stable high quality image, which meet the user demand for higher image quality and for video encode to provide a better choice.On inadequate clarity of CIF and disadvantage of high storage &high price of D1,the static playback resolution up to 360 TVline image quality in theory, over the image standard of VHS VTR 280 TVline in simulating industrial test,reach the standard level 2 of industry video to the ministry of public security and Level 3 project resolution requirements,meet the requirements of most video industry.
What is the CIF?
CIF (Common image formats)is the standard commonly image format. In H. 323 protocol ,it provisions the standard capturing resolution of the video capturing equipment.CIF = 352 x 288 pixels ,Full name of QCIF :Quarter common intermediate format.QCIF also is the Common Intermediate Format.In H. 323 provisions:QCIF = 176 x 144 pixels.
The characteristics of the CIF format :
(1) The television image spatial resolution for the resolution of VHS (Video Home System, VHS), that is 352 x 288 ;
(2) using the non - interlaced scan;
(3) Using the NTSC frame rate, television images of the largest frame rate is 30 000/1001≈29.97fps/seconds ;
(4) Using the 1/2 PAL horizontal resolution, that is 288;
(5) The brightness and two color difference signal (Y, Cr and Cb) components encoded separately，with their value ranges ITU - R BT. 601. black = 16, white = 235,the maximum of difference color is equal to 240, minimum value is equal to 16.
What is D1?
For these people who stay the long time in industrial video monitoring system industry ,everyone thought D1 is the resolution of hard disk video recorder display&video recording & playback,actually ,D1 is the display format standard of digital TV system, divided into the total five kinds specifications as follow :
D1：480i format （525i）：720 x 480 (horizontal 480 lines, non - interlaced scan),which as the same clarity with NTSC analog TV,horizontal frequency is 15.25 kHz, equivalent to what we call 4 CIF (720 x 576)
D2：480P format （525p）：720×480（horizontal 480 lines, non - interlaced scan）,it is more clear to compare with DI non - interlaced scan, but as the same with non - interlaced scan DVD specification ，31.5 kHz of horizontal frequency .
D3：1080i format （1125i）：1920×1080（horizontal 1080lines, non - interlaced scan），HD Relax adopt the most resolution which up to 1920 × 1080i/60Hz,33.75 kHz of horizontal frequency .
D4:720 p format （750p）：1280×720（horizontal 720 lines, non - interlaced scan），Although the resolution is lower than D3, because of progressive scan, more people felt D4 visual effect more clearly than 1080I (the actual successive 540 lines) in market .But for personal feeling,D3 is more clear than D4 in under the maximum resolution of 1920 x 1920,especially for the text expression,the resolution is 1280 x 720 p / 60 HZ and the horizontal frequency is 45 KHZ.
D5:1080p format （1125p）：1920×1080（horizontal 1080 lines, non - interlaced scan）;Currently it is the highest standards of civil high-definition video with the 1920 x 1080 p / 60 HZ resolution and 67.5 KHZ horizontal frequency .
Standard of D1 and D2 is the highest standard of our general analog TV,but not a Real HD . D3 1080i standard is the basic standard of high-definition television,It can be compatible with 720 p format.but D5 1080P is just a professional standards, not a civilian level.Refer to the 60HZ above is just an ideally field frequency, and its horizontal frequency of 67.5 KHZ.
There is no such high horizontal frequency of television at present,actually there is only 24HZ，25HZ and 30Hz in 1080P frequency fields of professional area .
