With the development of sensor technology, the low-light performance of camera is greatly enhanced. In a dark environment, with the help of weak light, even starlight, the camera can still shoot a clear color surveillance picture. SONY FCB-EW9500H uses a new Starvis CMOS sensor. Compared with traditional infrared night vision, the advantages of FCB-EW9500H starlight full-color camera are as follows:
1, the image color, more content than the infrared black and white image.
2. Real-time monitoring and post-investigation and evidence collection can obtain more information;
3, no need for additional infrared lights, no light pollution, better concealment;
4, there is no additional fill light, the power at night is relatively small, more conducive to POE power supply, at the same time less heat, the camera system is more stable and reliable;
5, there will be no infrared overexposure, flashlight effect and other traditional infrared camera defects, see more clearly.
6. Application in some special scenarios. For example, in the parking lot at night, after the headlights are turned on, the infrared camera may completely fail to see the license plate and the front of the car. A full-color camera perfectly solves this problem, with the license plate and front of the car clearly visible.
SONY FCB – 9500 series star full-color video cameras, promote the development of the upgrade in the field of security monitoring, FCB – EW9500H | FCB – EV9500M | FCB – EV9500L is anti monitoring is an integral part of company in this field.
Before we explore starlight full color technology, let’s first understand a few basic concepts.
01 — Illuminance
Illuminance is the amount of light flux received per unit area. The unit is lx=lux.
When a candle shines on an area of 1m2, the brightness is about 1lux.
The following table shows the illuminance values for some common scenarios
Of course, the above illuminance value is only a reference value, not so accurate. Similarly, in the field of video surveillance, there is no clear standard for what illuminance camera counts as starlight level, which will be discussed in detail later. Generally, the light sensitivity of the camera mainly depends on the lens and image sensor, the lower the specified lux value, the better the light sensitivity of the camera.
Generally, manufacturers specify the minimum level of illumination a camera needs to produce an acceptable image. While such specifications are useful for comparing the sensitivity of cameras from the same manufacturer, they are less useful for comparing cameras from different manufacturers. This is because different manufacturers use different measurement methods and have different standards for generating acceptable images.
02 – Starvis
The concept of starlight camera has always been in the security industry, but the name of the more professional system should come from SONY.
SONY named some of its own backlight CMOS sensors with excellent low-light performance starvis series. This should be the source of the name Starlight full-color camera.
For Starvis, Sony’s official explanation is visibility under the starlight. In the industry, of course, it’s called starvision. The logo of starvis is registered and certified by Sony. It is generally not allowed to be used freely without authorization.
Sony defines Starvis technology as follows: STARVIS is a backilluminated pixel technology for CMOS image sensors for surveillance cameras, with a sensitivity of 2000mV or more per 1m2 (color specification products, 706cd/m2 light source imaging, F5.6, 1s accumulation equivalent).
This technology is mainly used in back-illuminated CMOS sensors, because it can receive light from the back of the sensor silicon substrate, increasing the amount of light in and reducing the light loss, and improving the sensitivity.
The sensitivity of each 1m2 sensor can reach 2000mV and above is called starvis sensor. How to measure the performance difference of different starvis sensors? Sony also introduced the SNR1s concept.
03 – SNR1s
SONY has adopted SNR1s as one of the indicators for quantitative evaluation of low-light picture quality of CMOS image sensors used in surveillance cameras.
The SNR1s is a CMOS image sensor for surveillance cameras. The smaller the value, the better the picture quality in low light.
The SNR of SNR1s is “signal-to-noise ratio,” where 1 is “semamount is 1 when noise is 1,” and in addition, s stands for “monitoring use.”
Measurement conditions specified by SNR1s
SNR1s measurement method
The 18% gray image was illuminated with a light source of 3200[K] from both directions and adjusted to 100[lx]. The camera was placed 1m away from the imaging surface of the image sensor from the gray image to measure the sensitivity [e-] and dark noise [e-], and SNR1s [lx] was calculated through the relationship.
When the value of this equation is 1, the corresponding illuminance is SNR1s[lx].
SNR1s values of some common Sony sensors
04 — Four factors that affect camera low light
Image sensor Image sensor photosensitive performance is one of the core factors to determine the low light effect of the camera, in addition to the above introduced Sony Starvis series CMOS backlight sensor, domestic manufacturers have also launched a number of good photosensitive performance of the sensor, the overall performance gap with Sony is still relatively large.
The larger the aperture of a large aperture lens, the more light will be absorbed into the sensor through the lens, and the better the effect will be. The square ratio of the number of adjacent apertures in the full-level aperture value is 1:2, so the illuminance of the lens with two adjacent aperture values is twice as different. This means that an F1.0 lens will get twice as much light as an F1.4 lens. It should also be noted that the larger the lens aperture, the smaller the depth of field will be. Processing chip video coding chip ISP noise reduction, automatic gain ability will affect the final imaging effect. Low-light enhancement algorithm When all hardware performance is the same, the final decision of the product low-light performance is the manufacturer’s algorithm, optimization ability. For example, through certain AI algorithm, the input incomplete information can be recovered. Some even have a dual sensor mode (a new Huawei technology that was introduced at the show in 21, the name is hard to remember), a black and white one to provide more detail, and a color one to provide color. The two images are then combined to enhance the camera’s low-light capability.
According to Xuan Zhantechnology (SONY’s official authorized distributor), the SONY FCB-EV9520L, which will be available in the first half of 2023, uses an upgraded version of Starvis 2. What surprises will it bring to users? We’ll see!