The photometric modeling of LEDs as generalized Lambertian sources (GL-Sources) is discussed. Non-Lambertian
LED sources, with axial symmetry, have important real-world applications in general lighting. In particular, so-called
generalized Lambertian sources, following a cosine to the nth power distribution (n≥1), can be used to describe the
luminous output profiles from solid-state lighting devices like LEDs. For such sources, the knowledge of total power (in
Lumens [Lms]), the knowledge of the output angular characteristics, as well as source area, is sufficient information to
determine all other critical photometric quantities such as: maximum radiant intensity (in Candelas [Cd = Lm/Sr]) and
maximum luminance (in nits [nts = Cd/m2]), as well as illuminance (in lux [lx = Lm/m2]). In this paper, we analyze this
approach to modeling LEDs in terms of its applicability to real sources.
In this paper, we discuss the mathematics, electronic hardware, and network software aspects of the HYper-Distributed
Robotic Autonomy (HYDRA) bio-inspired large neural network, proposed in a previous paper.
In this paper, the foundations of radiometry and photometry, based on Second Principle of Thermodynamics are
discussed, in terms of brightness (luminance), and etendue (Lagrange invariant) limitations of integrated lighting
systems. In such a case, the brightness is defined as phase-space-density, and other radiometric/photometric quantities
such as emittance, exitance, or irradiance/illuminance, power/flux, and radiant/luminant intensity, are also discussed,
including examples of integrated lighting systems. Also, technologic progress at Luminit is reviewed, including 3D-microreplication
of new non-diffuser microscopic structures by roll-to-roll web technology.
Automatic target recognition (ATR) can be accomplished by many methods, including recognition of vibrometric
signatures. In many cases, ATR is enhanced by photorefractive amplification, a two-wave mixing effect in which two
input beams form a dynamic holographic grating. One of the two beams (the pump) diffracts from that grating into the
other (the signal), assuming the characteristics of the signal. When the pump is much stronger than the signal, the
diffracted pump becomes a highly amplified signal beam. Traditionally, however, the frequency at which this
amplification can be applied is limited to <1/2πτ0, where τ0 is the decay time of the grating in the absence of a pump or
signal. We demonstrate that the amplification has no such limit in the case of vibrometry, which measures
frequency-modulated, rather than amplitude-modulated, signals. This is shown by constant photorefractive amplification
at frequencies up to >700 kHz in Cu:KNSBN, which has τ0 >100 ms (corresponding to a maximum amplification
frequency of 1.6 Hz).
An inexpensive, easily integrated, 40 Gbps photoreceiver operating in the communications band would revolutionize the telecommunications industry. While generation of 40 Gbps data is not difficult, its reception and decoding require specific technologies. We present a 40 Gbps photoreceiver that exceeds the capabilities of current devices. This photoreceiver is based on a technology we call "nanodust." This new technology enables nanoscale photodetectors to be embedded in matrices made from a different semiconductor, or directly integrated into a CMOS amplification circuit. Photoreceivers based on quantum dust technology can be designed to operate in any spectral region, including the telecommunications bands near 1.31 and 1.55 micrometers. This technology also lends itself to normal-incidence detection, enabling a large detector size with its associated increase in sensitivity, even at high speeds and reception wavelengths beyond the capability of silicon.
True 3D displays, whether generated by volume holography, merged stereopsis (requiring glasses), or autostereoscopic methods (stereopsis without the need for special glasses), are useful in a great number of applications, ranging from training through product visualization to computer gaming. Holography provides an excellent 3D image but cannot yet be produced in real time, merged stereopsis results in accommodation-convergence conflict (where distance cues generated by the 3D appearance of the image conflict with those obtained from the angular position of the eyes) and lacks parallax cues, and autostereoscopy produces a 3D image visible only from a small region of space. Physical Optics Corporation is developing the next step in real-time 3D displays, the automultiscopic system, which eliminates accommodation-convergence conflict, produces 3D imagery from any position around the display, and includes true image parallax. Theory of automultiscopic display systems is presented, together with results from our prototype display, which produces 3D video imagery with full parallax cues from any viewing direction.
Head-mounted or helmet-mounted displays (HMDs) have long proven invaluable for many military applications. Integrated with head position, orientation, and/or eye-tracking sensors, HMDs can be powerful tools for training. For such training applications as flight simulation, HMDs need to be lightweight and compact with good center-of-gravity characteristics, and must display realistic full-color imagery with eye-limited resolution and large field-of-view (FOV) so that the pilot sees a truly realistic out-the-window scene. Under bright illumination, the resolution of the eye is ~300 μr (1 arc-min), setting the minimum HMD resolution. There are several methods of achieving this resolution, including increasing the number of individual pixels on a CRT or LCD display, thereby increasing the size, weight, and complexity of the HMD; dithering the image to provide an apparent resolution increase at the cost of reduced frame rate; and tiling normal resolution subimages into a single, larger high-resolution image. Physical Optics Corporation (POC) is developing a 5120 × 4096 pixel HMD covering 1500 × 1200 mr with resolution of 300 μr by tiling 20 subimages, each of which has a resolution of 1024 × 1024 pixels, in a 5 × 4 array. We present theory and results of our preliminary development of this HMD, resulting in a 4k × 1k image tiled from 16 subimages, each with resolution 512 × 512, in an 8 × 2 array.