Principios de fotometría: instrumentos de medición (parle II)

Se designa con este nomre a todo instrumento que utiliza como detector alg&uacute;n elemento fotosensible. Este tipo de detectores transforman la luz en electricidad, transformaci&oacute;n que puede realizarse directamente o indirectamente a trav&eacute;s de una doble transformaci&oacute;n, de energ&iacute;a luminosa a t&eacute;rmina y de t&eacute;rmica a el&eacute;ctrica. (P&aacute;rrafo extra&iacute;do a modo de resumen)</em

Optical correlation based on the fractional Fourier transform

Some properties of optical correlation based on the fractional Fourier transform are analyzed. For a particular set of fractional orders, a filter is obtained that becomes insensitive to scale variations of the object. An optical configuration is also proposed to carry out the fractional correlation in a flexible way, and some experimental results are shown.Material digitalizado en SEDICI-CIC Digital gracias a la Centro de Investigaciones Opticas (CIOP), UNLP-CICCentro de Investigaciones ÓpticasFacultad de IngenieríaFacultad de Ciencias Exacta

Light-in-flight digital holography display

We present a digital speckle-pattern interferometric setup that can be operated at TV frame rates (30 ms) to display the locus of the points at which the optical-path difference between the reference and object beams is within the coherence length. Experimental results are shown

Optical correlation based on the fractional Fourier transform

Some properties of optical correlation based on the fractional Fourier transform are analyzed. For a particular set of fractional orders, a filter is obtained that becomes insensitive to scale variations of the object. An optical configuration is also proposed to carry out the fractional correlation in a flexible way, and some experimental results are shown.Material digitalizado en SEDICI-CIC Digital gracias a la Centro de Investigaciones Opticas (CIOP), UNLP-CICCentro de Investigaciones ÓpticasFacultad de IngenieríaFacultad de Ciencias Exacta

Decomposition of biospeckle images in temporary spectral bands

We present a method of analysis of images of dynamic speckle based on the filtering in frequency bands of the temporary history of each pixel. Butterworth filters are applied to the temporary evolution, and different images are constructed showing the energy in each frequency band. Different degrees of activity of the sample in study, presumably attributed to different origins, are found. The method is exemplified with images of bruising damage in fruits and of biological activity in germinating corn seeds. It is found that the activity in the bruised region of an apple differs from the activity of healthy regions in a certain characteristic frequency range. The activity of the embryo can also be distinguished from that of the endosperm in corn seeds during germination

Decomposition of biospeckle images in temporary spectral bands

We present a method of analysis of images of dynamic speckle based on the filtering in frequency bands of the temporary history of each pixel. Butterworth filters are applied to the temporary evolution, and different images are constructed showing the energy in each frequency band. Different degrees of activity of the sample in study, presumably attributed to different origins, are found. The method is exemplified with images of bruising damage in fruits and of biological activity in germinating corn seeds. It is found that the activity in the bruised region of an apple differs from the activity of healthy regions in a certain characteristic frequency range. The activity of the embryo can also be distinguished from that of the endosperm in corn seeds during germination

Decomposition of biospeckle images in temporary spectral bands

We present a method of analysis of images of dynamic speckle based on the filtering in frequency bands of the temporary history of each pixel. Butterworth filters are applied to the temporary evolution, and different images are constructed showing the energy in each frequency band. Different degrees of activity of the sample in study, presumably attributed to different origins, are found. The method is exemplified with images of bruising damage in fruits and of biological activity in germinating corn seeds. It is found that the activity in the bruised region of an apple differs from the activity of healthy regions in a certain characteristic frequency range. The activity of the embryo can also be distinguished from that of the endosperm in corn seeds during germination.Facultad de Ingeniería (FI)Centro de Investigaciones Ópticas (CIOp

Optical correlation based on the fractional Fourier transform

Some properties of optical correlation based on the fractional Fourier transform are analyzed. For a particular set of fractional orders, a filter is obtained that becomes insensitive to scale variations of the object. An optical configuration is also proposed to carry out the fractional correlation in a flexible way, and some experimental results are shown.Digitalizado en SEDICI-CIC Digital

Decomposition of biospeckle images in temporary spectral bands

We present a method of analysis of images of dynamic speckle based on the filtering in frequency bands of the temporary history of each pixel. Butterworth filters are applied to the temporary evolution, and different images are constructed showing the energy in each frequency band. Different degrees of activity of the sample in study, presumably attributed to different origins, are found. The method is exemplified with images of bruising damage in fruits and of biological activity in germinating corn seeds. It is found that the activity in the bruised region of an apple differs from the activity of healthy regions in a certain characteristic frequency range. The activity of the embryo can also be distinguished from that of the endosperm in corn seeds during germination.Facultad de Ingeniería (FI)Centro de Investigaciones Ópticas (CIOp

Fully digital encryption technique

We propose an alternative fully digital encryption technique based on using the Fourier transform of the original object to be processed and a speckled reference wave as encryption mask. Once encrypted, the Fourier transform spectrum of the object is holographically stored. The original data recovering is performed by digital reconstruction using the same encryption mask, which is also holographically stored. Quality of reconstructed data is evaluated as a function of the sensed encrypted data. Computer simulations and experimental results are presented to demonstrate the method