The images obtained from the cryo-electron microscopy are usually very noisy and have very low contrast. It is quite necessary to smooth the noise as well as enhance the contrast before other tasks can be conducted. This also happens right after the 3D electron density maps are reconstructed. We have developed an adaptive contrast enhancement technique and a PDE-based anisotropic diffusion technique for noise removal. The following pictures show an example of our approaches on the reconstructed electron density map of Rice Dwarf Virus (RDV). More details are available later or upon request. The Cryo-EM images or the reconstructed maps may also be improved by Contrast Transfer Function (CTF) correction. However, we are not working on this.

Fig. 1    Left: original image	Middle: after anisotropic filtering	Right: after contrast enhancement

Fig. 2 Left: original image	Right: after anisotropic filtering