3. Spatial Frequency Control Processing

Spatial Frequency Control processing is the process of controlling sharpness. In a film screen system, the higher the frequency becomes, the smaller the frequency response becomes. However, with CR it is possible to control response as desired. In FCR, unsharp mask processing is used as a method of image processing for frequency control.

Below is the basic explanation of unsharp mask processing in one dimension: (N < object size)

The Fuji spatial frequency processing is divided into three attributes. These three attributes are RE, RN, and RT. RE is the “brightness” assigned to pixels which comprise the edge of the image. RN, is the “width”, in a relative number of pixels, of this edge. The RT value allows the user to selectively apply edge enhancement to a given area of the image based on a selected density range. This range is established through a selection of various density distribution curves. This overcomes the fact that when edge enhancement is applied overall to an image, the lower density areas create a great deal of unnecessary “noise”. By selectively applying this edge enhancement to selected density areas greatly improves the image without creating excessive noise.