[Reprinted] explanation of AE built-in image extraction plug-in

As early as when film effects were still dominated by SGI platforms, after effect (hereinafter referred to as AE) was the earliest synthetic software for low-end personal platforms (PCs & MAC. With the strength of Adobe to dominate the printing and publishing industry, AE now has the widest user base on low-end platforms. So its various Synthesis tools and methods are also representative.

In the latest version 5.0 released by AE, there are nine built-in Imaging tools. Designers put them as a type of effect under the effect | keying menu.
These nine built-in image extraction tools and their functions are:

Color Difference key (color difference): Performs image extraction based on the color difference in the image.

Color Key: Specifies an image color to perform image extraction.

Color Range: Specifies a color range in any color mode of RGB, lab, or YUV to produce transparency.

Difference matte: Performs image extraction based on the differences between the two images on the same background.

Extract (image extraction): creates transparency by specifying a brightness area of an image. It works based on a bar chart of a specified channel.

Inner outer key: (inside and outside of the image) specifies the input and output ranges in the image for the image.

Linear Color Key establishes transparency by specifying RGB, tone, or saturation information on colors.

Luma key specifies the brightness or contrast of an image to exclude the specified color information of all regions on the image. However, the image quality of this layer is not affected.

Spill suppressor (Limit overflow) is used to clear the residual background color of a completed subject. It is often used to remove the remaining image color at the edge of the image. The target object is the background color that is reflected to the object through the light.