An optical system formed by four point-diffraction interferometers is used for measuring the refractive index distribution
of a phase object. The phase of the object is assumed enough smooth to be computed in terms of the Radon Transform
and it is processed with a tomographic iterative algorithm. Then, the associated refractive index distribution is calculated.
To recovery the phase from the inteferograms we use the Kreis method, which is useful for interferograms having only
few fringes. As an application of our technique, the temperature distribution of a candle flame is retrieved, this was made
with the aid of the Gladstone-Dale equation. We also describe the process of manufacturing the point-diffraction
interferometer (PDI) plates. These were made by means of the thermocavitation process. The obtained three dimensional
distribution of temperature is presented.
An optical-digital method is proposed for restoring trichromatic images out-of-focus, detected with a monochromatic
CCD. The optical system (OS) is a microscope working in bright field mode and the source of illumination is
polychromatic. To carry out the restoration, an estimated of the intensity point spread function is obtained from the
image of a non-resolved object (quasi-point source) by the OS in three wavelengths. From the image of the quasi-point
source, its spectrum is calculated for obtaining the optical transfer function associated with each wavelength. The
Wiener filter is built with the spectrum, and the restoration is made for each color. By an addition of the three restored
images, an estimated of the trichromatic object is recovered. The obtained results and conclusions are presented.
In this work, experimental results are obtained from the behavior of the Discrete Wigner Distribution Function (DWDF),
when is applied on a detected image of an object of small dimensions, non-resolved by the optical system (OS). The
object is illuminated with a laser source. We verify that for the average of several detected images the DWDF is positive
inside a frequency interval of four times the bandwidth of the OS. However, when the object is not a quasi-point source
the DWDF has positive and negative values inside the same interval. This is an indication that in this case the object is
resolved by the OS. Numerical and experimental results are shown and compared to support this conjecture.