A smoothing operation is frequently a first step in operations such as noise reduction, edge detection or interpolation. A commonly used smoothing filter has constant coefficients. The effect of smoothing or blurring an image is achieved by convolving the image with such a filter. The simplest form of unsharp masking may be implemented by subtracting a scaled smoothed image from the original. Here we display the three results.
Edge detection is an important step in many shape-based recognition tasks.
Edge detection is typically implemented as a convolution operation with appropriately chosen differentiating filters.