Night Vision Q&A
Night vision is an important feature which keeping you an eye on your loved ones at night. Let's us talk about this function and answer some common-seen problems in this article.
CMOS sensor cannot capture images without light. So, there are infra-red (IR) LEDs at the baby camera emit IR light at dark, providing light to CMOS for image capture. IR light is invisible to human eyes, so the environment remains 'dark' but you can see the image from the baby monitor.
There are 2 different sets of CMOS settings for day mode and night vision mode, like exposure time, saturation, brightness ..etc. To decide when the night vision mode kicks in, there is a light sensor equipped at the baby camera to detect ambient light level. The firmware collects data from the light sensor and decide when the night vision mode should be enabled or disabled.
After basic logic, let's talk about some common-seen issues with the night vision :
1. I got a defected unit. My baby monitor only shows black and white images, not color as advertised.
Black and white images come from night vision mode. Probably you have accidentally set the night vision setting to 'On', and cause the problem. Set it back to 'Auto', and bring your baby camera to a bright area. It should give you a colored image back. If not, you should contact your manufacturer for further assistance.
2. Night vision kicks in too early/late. The baby room is not dim at all.
From developer view, we examine the FPS (frame per second) generated by CMOS on different light level environment (data collected from light sensor), then decide when the night vision kicks in. We aim to guarantees a comfort FPS at day mode viewing.
From user practice, you need to make sure the light level reaching your baby is the same (or close) as reaching the light sensor. For example, if you put the camera inside a cabinet, it may be dimmer than your baby crib, and cause an early kick-in of night vision.
On the other hand, instead of using 'Auto' mode, you can manually turn on or off the night vision, if necessary.
3. Night vision mode blinking / on and off repeatedly!
First, lets explain how it happened. Light sensor triggers night vision mode on and off by detecting light intensity. But, IR light is a light itself. When IR LEDs turn on at night vision mode, the IR light hits a highly reflective object and reflects back to the light sensor, it may cause the blinking problem. The case looks like dim area > IR LEDs turn on > IR light reflects back to light sensor > baby monitor misinterprets a bright condition > IR LEDs turn off > dim area and repeat...
Some good light sensor itself can filter off partial IR light intensity, but not all. So, experienced designer will create an angle (90 degree the best) between IR emission and the light sensor reception area. As a result, the sensor is not likely to be affected by IR light reflection.
From user view, you can also try to put away any highly reflective object (like mirror, gloss surface) from the IR emission zone. Adjusting the camera location or angle will help too, when you understand above mentioned symptoms.
Hope you find this article helpful. Drop me a message if you have any question.
Happy baby monitoring!