We describe a simple method for visualization of phase objects. The phase object is placed between a printed two-dimensional periodic pattern and a CCD camera. The ray deflection that is due to the phase object distorts the image of the pattern. This image is subtracted from a reference image and then, by squaring and low-pass filtering, a measurement of the two-dimensional refractive-index changes is obtained. Because the optical system does not require special alignment or illumination, the method presented has potential application for detection of gas leaks in industrial environments.
© 2000 Optical Society of America
(100.5070) Image processing : Phase retrieval
(120.4630) Instrumentation, measurement, and metrology : Optical inspection
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
César D. Perciante and José A. Ferrari, "Visualization of Two-Dimensional Phase Gradients by Subtraction of a Reference Periodic Pattern," Appl. Opt. 39, 2081-2083 (2000)