Nonlinear optical Fourier filtering technique for medical image processing

Sri Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D. V.G.L.N. Rao

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Real-time nonlinear optical Fourier filtering for medical image processing is demonstrated, exploiting light modulating characteristics of thin films of the biophotonic material bacteriorhodopsin (bR). The nonlinear transmission of bR films for a 442 nm probe beam with a 568 nm control beam and vice versa is experimentally studied in detail. The spatial frequency information carried by the blue probe beam is selectively manipulated in the bR film by changing the position and intensity of the yellow control beam. The feasibility of the technique is first established with different shapes and sizes of phantom objects. The technique is applied to filter out low spatial frequencies corresponding to soft dense breast tissue and displaying only high spatial frequencies corresponding to microcalcifications in clinical screen film mammograms. With the aid of an electrically addressed spatial light modulator (SLM), we successfully adapt the technique for processing digital phantoms and digital mammograms. Unlike conventional optical spatial filtering techniques that use masks, the technique proposed can easily accommodate the changes in size and shape of details in a mammogram.

Original languageEnglish (US)
Article number044028
JournalJournal of Biomedical Optics
Issue number4
StatePublished - Jul 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering


Dive into the research topics of 'Nonlinear optical Fourier filtering technique for medical image processing'. Together they form a unique fingerprint.

Cite this