Performance Comparison of Image Processing Techniques on Various Filters: A Review

2. Filtering Techniques

The three primary filtering techniques that have been opted for analysis are the high pass, low pass, and median filtering techniques. The low pass filters are majorly used for removing the high-frequency noise content from real-time-images. This involves smoothing of sharp edges. The noise content can of Gaussian type, or uniform or Rayleigh or else in nature. This filter can be further categorized as Low Pass Averaging Filter and Low Pass Median Filter. These filter techniques use masking techniques that blur the sharp edges of the image under consideration. When the mask is applied to the image, it reduces the sudden transition of the pixel values resulting in a reduction of sharp edges.

Figure 1.

The average mask used for the low pass filtering technique

The above image shows a typical 3*3 matrix mask used for common filtering techniques. As shown, the sum of elements of the matrix equals to one. To implement the mask, the image undergoes the following mathematical expression, where w (n), such that n=1, 2, 3…9 corresponds to the corresponding elements of the masking matrix: