通道抠像节点
通道抠像 节点依据选择的通道值差异定义背景对象和前景对象。
比如在YUV(亮度信号,色度信号)颜色空间,当合成在实体暗色调背景爆裂激发(非常明亮)类素材是非常有用的。
输入
- 图像
Standard color input.
属性
- 色彩空间
这个按钮设置采取哪种颜色空间作为显示方案。
RGB(红绿蓝), HSV(色度饱和度明度), YUV(亮度信号,色度信号), YCbCr(亮度,蓝色和红色偏移量成分)
- Key Channel
This button selects the channel, defined by the Color Space, to use to determine the matte.
- 算法
Method to calculate the difference between levels.
- 最大值
Limit by the maximum of the other two channels other than the Key Channel.
- 单一
Limit by the maximum of the selected Limiting Channel.
- 限定通道
The channel to use when computing the maximum, the options are defined by the Color Space.
- 高
Determines the lowest values that are considered foreground. (Which is supposed to be -- relatively -- high values: from this value to 1.0.)
- 低
确定被视为前景的最低值。(相对而言,高度值:从此值到 1.0)
Tip
It is possible to have a separation between the High and Low values to allow for a gradient of transparency between foreground and background objects.
输出
- 图像
由遮罩选择部分处理的带alpha通道的图像。
- 蒙版
通过操作形成黑白alpha遮罩结果。