this program is in java and it can be used to apply various filters to an image.low pass filter,high pass filter,mean filter,median filter can be applied to an image opened using file dialog box

This java applet is a demonstration of digital filters. You should hear a noise waveform when the applet starts up. If you get a message "Need java 2 for sound", then you should get the Java plug-in. The applet starts up with a low-pass filter.

布莱克曼低通滤波器，Blackman bandpass filter-Blackman low-pass filter