[IP3-6-1] Combined filtering

Combined filtering uses different filters to arrive at more complex filters for specific purposes. For example, Laplacian filters are derivative filters used to find areas of rapid change (edges) in images. Since derivative filters are very sensitive to noise, it is common to smooth the image (e.g., using a Gaussian filter) before applying the Laplacian. This two-step process is called the Laplacian of Gaussian (LoG) operation.

External resources

• Don Matthys. (2001). Laplacian of Guassian Filter. Retrieved from https://academic.mu.edu/phys/matthysd/web226/Lab02.htm
• Jensen, J. R. (2005). Introductory digital image processing: a remote sensing perspective (3rd ed.). Upper Saddle River, N.J.: Prentice Hall.

Learning outcomes

• 1605 - Compare results of the Laplacian of Gaussian filter to the original input image

  Compare results of the Laplacian of Gaussian filter to the original input image

• 2316 - Identify and discuss an example of a combined filtering process

  Identify and discuss an example of a combined filtering process

Self assessment

Outgoing relations

• [IP3-6-1] Combined filtering subclassof [IP3-6] Neighbourhood analysis (convolution)

Incoming relations

• [IP3-9-1] Difference of Gaussian (DoG) subclassof [IP3-6-1] Combined filtering