Search

The closed-form propagation equation of Gaussian beams through a paraxial optical ABCD system is derived using the fractional Fourirer transform and its general applicable advantage is illustrated with numerical examples. [ABSTRACT FROM AUTHOR]

This work show a image adquisition system implemented in a FPGA (Field Programmable Gate Array), which can be applied at image an video processing in real time; in the system was used a analog video camera, a analog-digital converter for video signal, and data storage memory. Additionally a digital filter system is implemented on the FPGA for to extract characteristics of the acquired images. The system can synchronize itself with the video signal of any format (NTSC, PAL, and others), to digitize the image of this signal, which is storaged for its processing. [ABSTRACT FROM AUTHOR]

Iso-dose maps creation and kerma-area products calculation are important procedures in radiotherapy and medical imaging. In this work, a method is presented to obtain iso-dose maps through digital processing of the images obtained from radiochromic films, which are employed to estimate the dose absorbed by the patient. The kerma-area product in selected regions of interest (ROIs) in the iso-dose map was then evaluated. The images were obtained by scanning the irradiated films using a commercial flatbed scanner. The iso-dose areas were extracted by means of an image segmentation algorithm, while calibration for a particular film to obtain a sensitometric curve relating dose to film darkening, was also made. A software interface allowed introducing the scanned image for the estimation of kerma-area products by defining the ROI interactively. The methods developed in this work allowed to implement a software application to obtain the iso-dose maps and kerma-area product in selected ROIs. [ABSTRACT FROM AUTHOR]