Edge NodeThe Edge Node enables you to select from several effective methods for performing edge-detection. Typically, the input to the Edge node is a foreground element that will subsequently be composited. The output of the edge node is often used as a control image in blurs, dissolves, and other operations to improve the realism of composites by softening or otherwise adjusting foreground edges. The Edge node identifies edges by comparing each pixel with surrounding pixels. The pixel currently being processed is the center pixel in a kernel (a matrix, or grid) that you specify using the Edge node parameters. Edge Parameter Tab![]() MethodThis parameter enables you to choose from the following edge-detection methods: These options are listed in order of computation speed, from fastest (Roberts) to slowest (Kirsch). The best method to use will depend on your imagery; however, the default is Sobel, which usually provides excellent results without resorting to the much more computationally intensive Kirsch operation. Filter Width / PixelsThe Filter Width and Pixels parameters enable you to specify the size of the kernel, or operation area, used by the Sobel or Kirsch methods. When Roberts is the selected method, the Filter Width tuner is grayed out and only the Pixels field is used to adjust the effect. The Filter Width parameter and the Pixels parameter are tied; that is, when you adjust one, the value of the other updates accordingly. The value in the Filter Width tuner is expressed as a percentage of the width of the image, in a range of 0-1. The value in the Pixels field is expressed as an odd number of pixels (if you do enter an even number, Chalice automatically adjusts the value to the next lower odd value). BorderThe pixel currently being modified is in the center of a grid of pixels that define the operation area. Therefore, when processing a pixel that borders the image (or when the operation area is sufficiently large), there will not be adjacent pixels on all sides to contribute to the calculation. The Border parameter enables you to specify how border pixels should be treated by selecting one of the following options from the Border popup menu:
Channel MaskThe Channel Mask parameter enables you to inhibit the modification of any channel by deselecting the Red, Green, Blue, Alpha, or Other channel icons. Control Image ParametersThe Control Action and Control Channel menus enable you to specify how an optional control image input will govern the node operation, as explained in "Using Control Images with Filter Nodes ." |