What is SNR in relation to CCTV Security Cameras


What is SNR (signal to noise ratio) and how does it relate to CCTV Security Cameras?


The signal to noise ratio is measured in decibels. The higher the dB number the better the picture. Meaning it has less noise in the picture. Noise can be manifest in graininess, loss of detail, etc. WDR (Wide Dynamic Range) cameras are 95 dB typical and 120 dB maximum providing noise free images. Typical CCTV Security cameras are around 50 db S/R. The chart below gives you an idea of what the effects of various SNR levels will do to the picture quality.

S/N Ratio DBS/N Ration:1Picture Quality
60 dB1,000Excellent, no noise apparent
50 dB316Good, a small amount of noise but picture quality good.
40 dB100Reasonable, fine grain or snow in the picture, some fine detail lost.
30 dB32Poor picture with a great deal of noise.
20 dB10Unusable Picture

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