IR-Cut in our System
I was first noticed of the IR Cut-Off Filter by the sensor board connector schematic diagram:
Pin 35 and Pin 36 illustrate IRCUT_CONTROL, which do NOT have any connections with the IMX chip. Reminded by the sensor board retailer, I went on search engine, and realised that IR_CUT filters mechanism is widespread in network / security camera.
In short, the two IRCUT pins are to be connected to a dedicate IRCUT filter mechanism to switch between IR-Cut filter and all-pass (not sure about the name) filter.
What is IR-Cut?
There is a nice article about IR-Cut:
|What’s IR-Cut infrared security camera ?|
IR-Cut security camera is the security camera has a IR-CUT filter built-in to make camera provide true color reproduction high quality image at day and night. The function of IR-cut in security camera is fixing the color distortion, meanwhile maintaining good light sensitivity at night.
When a security camera works at day, people want to get the accurate color images, the equipped IR-cut filter will block the infrared light (from outside), so infrared light will not enter into the image sensor (CMOS/CCD). If the infrared light enters to the image sensor at day, it will interfere the color reproduction.
Here is a Chinese version.
Effect of IR-Cut
Source for IR-Cut
For easy integration, there are lots of existing IRCUT solution on taobao: Search IRCUT on taobao, at very affordable price.
Also, alternatively, there are also IR-Cut Filters available for us, such as:
It appears that the control is simply GPIO, which then go through power amplifier for mechanical controls.
As we are not shooting at night, we do not need a switchable IR-Cut mechanism. But purchasing an IR-Cut filter itself for our system seems necessary. As it improves image quality by a lot.