Wavelet-based image restoration for compact X-ray microscopy.
Compact water-window X-ray microscopy with short exposure times will always be limited on photons owing to sources of limited power in combination with low-efficency X-ray optics. Thus, it is important to investigate methods for improving the signal-to-noise ratio in the images. We show that a wavelet-based denoising procedure significantly improves the quality and contrast in compact X-ray microscopy images. A non-decimated, discrete wavelet transform (DWT) is applied to original, noisy images. After applying a thresholding procedure to the finest scales of the DWT, by setting to zero all wavelet coefficients of magnitude below a prescribed value, the inverse DWT to the thresholded DWT produces denoised images. It is concluded that the denoising procedure has potential to reduce the exposure time by a factor of 2 without loss of relevant image information.
Stollberg
H
H
Biomedical and X-ray Physics, Royal Institute of Technology/SCFAB, SE-10691, Stockholm, Sweden.
Boutet de Monvel
J
J
Holmberg
A
A
Hertz
H M
HM
D000465:Algorithms; D016477:Artifacts; D017377:Diatoms / Q000648:ultrastructure; D007089:Image Enhancement / Q000379:methods*; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D012815:Signal Processing, Computer-Assisted; D014965:X-Rays