Sony is introducing SNR1s [lx] as an index used to quantitatively evaluate picture quality at low illumination. SNR1s [lx] is a proprietary index advocated by Sony, and is limited to CMOS image sensors for security camera applications.
A smaller value indicates better picture quality at low illumination.
SNR1s [lx] is an acronym consisting of "SNR" (Signal-to-Noise Ratio), "1" (represents that the signal level when noise = 1 is 1), and "s" (for Security).
|Light Source||3200 [K]|
|Target Object||18% Grey|
|Exposure time||1/60 [s]|
|Signal||G [e-] (Sensor Raw Output)|
|Signal : Noise||1 : 1|
Figure 1 shows a schematic of SNR1s measurement.
Two 3200 [K] light sources illuminate an 18% gray chart from different directions, and dimming is performed to 100 [lx]. A camera is placed so that the distance from the gray chart to the imaging surface of the image sensor is 1 m, the sensitivity [e-] and dark noise [e-] are measured, and SNR1s [lx] is calculated using the relational equation (1). The luminance when equation (1) equals 1 is SNR1s [lx].
For further details, contact your local Sony sales company.
Fig.1 Schematic of SNR1s Measurement
|Resolution||Image size||Products||SNR1s value|
|5M to 6M||1/2||
|2M to 2.4M||1/2||
|1M to 1.3M||1/3||