A quadratic cost functional for computing an estimate of a wave front from multiple directional derivatives is presented. This functional is robust to noise and is specially suited for moiré deflectometry, Ronchi testing, and lateral shearing interferometry.

In this article, the use of a square Hartmann screen test to measure the radius of curvature of a corneal topography calibration test sphere is presented. The proposed technique is based on the image formation principle by specular reflection on convex reflective surfaces. Applying an inverse Hartmann test, a de-magnified virtual image (Hartmanngram) is obtained; considering their own scaled reference screen plate, a zonal wavefront retrieval approach is used and the radius of curvature obtained. Experimental setup along the obtained results is presented. A simulated spherical wavefront is used as a method to evaluate the error in the wavefront reconstruction. Since the measurements of radius of curvature fits in to ISO 10343, through suitable modifications the proposed method is potentially applicable in small F/# convex specular surfaces, as is the case in keratometry and corneal topography measurements.

The use of optical imaging technology in recent years has improved diagnostics in the dermatology area. The techniques that can be named are optical coherence tomography, Raman spectroscopy, and optoacoustic imaging. Each technique has applications in general medicine and dermatology but with their respective limitations and focus. This work reviews the imaging techniques in general, prioritizing the theoretical background that allows the technique to operate, and then an image example obtained with the technique is shown. Then, an extensive review of the techniques of hyperspectral imaging and hyperspectral polarized dermatoscope is made. Finally, we talk about new trends in optical imaging future.

En el presente trabajo se propone implementar una técnica de transformación de coordenadas para aplicar el método de Transformada de Fourier para el análisis de interferogramas que incluyan un patrón de franjas cerradas. Inicialmente, el patrón de franjas concéntricas es convertido a un patrón de franjas lineales mediante una transformación de coordenadas cartesianas a polares. La distribución de fase para el patrón de las franjas lineales es determinada por el método de Fourier convencional. El mapa de fase del patrón original de franjas cerradas es obtenido mediante una transformación de coordenadas inversa. Ahora, de un sistema de coordenadas polares se regresa a un sistema de coordenadas cartesianas. Los resultados preliminares muestran la validez de la técnica propuesta.

We determined the in vivo absorption coefficient (μ_a) for 82 test subjects, all classified as Fitzpatrick skin phototypes II, III, IV, and V. Measurements were conducted using the integrating-sphere technique on the dorsal and palmar surfaces of the hand and the forearm. The reflectance data obtained were processed using the Inverse Adding Doubling algorithm to calculate the absorption coefficient. The mean values for this parameter ranged from 0.0132 mm⁻¹ to 0.1021 mm⁻¹ at a central wavelength of 624 nm. It was found that these parameters may be grouped into a distinct cohort, paving the way for studies and the design of light-based diagnostics and treatments better suited to the population in Mexico and Latin America.