Sharpen Images

Topaz Sharpen™ is a powerful filter that can increase the sharpness of an image. Unlike other sharpening filters, it can do so without the usual overshooting, ringing edges, or noise amplification. In addition, it can be used to reduce aliasing and achieve other effects.

The image on the top has a slight blur caused by bad focus. Athe Topaz Sharpen™ filter and set the parameters as indicated in the table in the next page. The result at the bottom is a lot better. As you can see, Topaz Sharpen™ effectively enhances the image sharpness and produces a natural-looking result.

There are eight parameters in total that control the different aspects of Topaz Sharpen. “Sharpness” controls the overall sharpening. This parameter has behavior similar to a regular sharpen filter. An inappropriately high value will produce overshooting or a “ringing edge”.

“Radius” controls the size of edges to be sharpened. It should be set according to the size of the blur. In our example, the blur is not severe; therefore a small value of 0.7 is used. Larger values should be used for more severe blur situation. However, a larger radius tends to destroy small details.

“Edge Crispness” is a unique capability of Topaz Sharpen™ which synthesizes crisp edges of images. Higher value will produce more crisp edges without the ringing edges or overshooting. However, an overly high value may produce unnatural images.

“Line Accent” is another very unique capability of Topaz Sharpen™, which emphasizes line features. The filter examines the image for lines and accentuates these lines according to the “Line Accent” setting. Proper use of this parameter can produce smooth looking edges and reduce noise at the same time. Again, an overly high value may produce unnatural images.

“Horizontal Aliasing Reduction” works together with “Line Accent”. It reduces the aliasing effect on strong horizontal edge lines. Horizontal aliasing can be identified as “staircase” horizontal lines or edges, instead of smooth horizontal lines. You must set “Line Accent” to high value, e.g. >0.5, for this feature to be effective. “Vertical Aliasing Reduction” is similar to “Horizontal Aliasing Reduction”, except it works for vertical lines. “Iterations” enables you to process the image through Topaz Sharpen™ multiple times. These will enable you to strengthen the effect of Topaz Sharpen™.