Gradient field microscopy of unstained specimens: comment.
We comment on a recent paper by Kim et al. [Opt. Exp. 20(6) 6737-6745 (2012)], in which the authors claimed to present a new method for first-order differentiation of phase objects called gradient field microscopy (GFM). We consider that the method does not substantially differ from well-known Fourier methods discussed in textbooks. Also, we discuss some deficiencies of the paper.
Instituto de Física, Facultad de Ingeniería, UdelaR, J. Herrera y Reissig 565, Montevideo, Uruguay. jferrari@fing.edu.uy
José A
JA
Ferrari
Gastón A
GA
Ayubi
D007089:Image Enhancement / Q000295:instrumentation*; D008029:Lighting / Q000295:instrumentation*; D008853:Microscopy / Q000295:instrumentation*