RESUMO
Signaling by spatial coding is proposed for asynchronous multiple-access free-space optical communications and interference mitigation. The large spatial bandwidth (e.g., 10(6) pixels) of each laser transmitter aperture is utilized for user coding, while the transmitter temporal bandwidth is preserved for information signals. Signal recovery is based on incoherent optical detection, spatial sampling, and electronic or optical matched filtering of the remotely received transmit optical beam Fresnel or Fraunhofer diffraction pattern. The proposed signaling method is appropriate for multiple-access free-space laser links involving multiple transmitters that use a common receiver. With electronic filtering, low-to-medium (e.g., 3 Mbits/s) data-rate users are appropriate. With a lenslet-array-based incoherent optical correlator, higher (e.g., 100 Mbits/s) data rates can be achieved. Improved interference protection is achieved cby spatially distributed bit-duration-based processing. Preliminary simulation results are carried out to demonstrate operating principles.
RESUMO
A brother and sister born to normal, nonconsanguineous parents have a syndrome of profound sensorineural hearing deficiency, enamel hypoplasia limited to the permanent dentition, and nail abnormalities. This appears to be a previously unreported inherited syndrome.
Assuntos
Hipoplasia do Esmalte Dentário/genética , Perda Auditiva Neurossensorial/genética , Unhas Malformadas , Anormalidades Múltiplas/genética , Criança , Feminino , Humanos , Masculino , SíndromeRESUMO
This paper presents a new concept for recognizing target shapes. The method depends upon establishing a uniform current density in a mesh of interconnected photosensitive pixels and characterizing the target image by potential changes at the mesh boundary. The concept proposes a way to reduce potentially hundreds of thousands of pixel values to a small set of signature values. The concept also removes the traditional time bottleneck of having to read the image off the focal plane before commencing analysis. The method is capable of easily handling target rotation and linear scaling.
