All digital images can benefit from being sharpened. This is especially true for enlarged images, but enlarged or not, all captured images – digital or analog – suffer from blurring or softening of detail in some way. This is precisely the motivation behind Kneson Software’s addition of the Resharp function in Imagener Professional and Imagener Unlimited. However, our customers have been asking for more information about this function as use of it does require a certain level of skill and knowledge to master.
Blurring occurs when the representation of an object is at a lower contrast or retains less detail than is present in the original. Sharpening compensates for this loss by improving the visibility of the information in the image. It works by applying a matrix of numbers over an array of the pixels in the image with the matrix centered over one pixel at a time. Sharpening can add image data that improve the appearance or impression of sharpness.
This function is formally known as “Unsharp Mask.” We named it “Resharp” to avoid any confusion, but the technique is actually a darkroom technique for improving the sharpness of paper prints that were used before the age of digital pictures.
There are three variables to the function, Amount, Radius, and Threshold. Each variable interacts with the other so it is possible to obtain nearly identical effects with very different settings. Keep the following characteristics in mind: