This filter is designed to eliminate noise from relatively slowly varying regions of the image. If the range of intensities within the filtering cell is less than a user-specified limit, then a low pass convolution will be used. If the range exceeds the limit, convolution of successively smaller cells will be used until either the cell consists of only a single pixel or the range is satisfied.
This filter is designed to eliminate noise from an image with an intensity close to zero (black). The filter determines the minimum intensity in a mxn cell. If this is equal to zero, then the corresponding centre pixel will have its intensity set to zero.
This filter uses a mxn cell to replace the pixel at the centre of the cell by the maximum value of the pixels in the mxn cell.
This filter is similar to D except that the minimum value of the pixels in the mxn cell is used to replace the centre value.
This filter replaces the central pixel with the nineth root of the product of the pixels in the mxn cell.
This filter is designed to act as a low pass filter on regions where the intensity is varying very rapidly, yet have no effect on more subtle variations. If the range of intensities within the filtering cell is more than a user-specified limit, then a low pass convolution will be used. If the range does not exceed the limit, then no further action will be taken.
This filter is related to D and E and replaces the central pixel in the mxn cell by the mean of the minimum and maximum intensities of the pixels in the cell.
This filter is similar to M except instead of using the average of the min and max values in the mxn cell, it uses the difference between them.
If the pixel at the centre of the template has an intensity higher than any of the other pixels in the template, then its intensity will be set to the maximum of those pixels. Similarly, if the intensity is lower, then it will be set to the minimu.
This filter is simular to the low pass convolution filters except that it computes the rms mean of the mxn cell and uses this as the new intensity for the central pixel.
This filter is effectively a high pass filter. The central pixel in the cell is replaced by the standard deviation of all the pixels falling in the cell.
This filter is designed to eliminate noise from an image with an intensity close to 255 (white). The filter determines the maximum intensity in a mxn cell. If this is equal to 255, then the corresponding centre pixel will have its intensity set to 255.