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).
SNR1s [lx] Prescribed Conditions | |
---|---|
Application | Security Camera |
Light Source | 3200 [K] |
Target Object | 18% Grey |
F number | 1.4 |
Exposure time | 1/60 [s] |
Linear Matrix | without |
Signal | G [e-] (Sensor Raw Output) |
Noise |
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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's sales company.
Note:SNR1s is a new index proposed by Sony for picture quality at low illumination, and is limited to CMOS image sensors for security applications.