772 results about "Spectral properties" patented technology

A class of bandwidth reduction techniques are used develop a broad class of modulation types collectively called SSB-FM. These signals can be used to construct communication systems that provide bandwidth-normalized performance gains of 10 dB or more when compared to popular prior art modulation methods. An aspect of the invention involves mapping trellis paths in a complex signal space onto corresponding real-valued trellis signals with desirable spectral properties. The invention can be used map continuous phase modulated (CPM) signals onto simpler amplitude-modulated trellis signals having double the channel capacity of prior art CPM signals. Multi-amplitude signaling and frequency division multiplexing may also be incorporated to further accommodate more information per symbol.

A multispectral X-ray imaging system uses a wideband source and filtration assembly to select for M sets of spectral data. Spectral characteristics may be dynamically adjusted in synchrony with scan excursions where an X-ray source, detector array, or body may be moved relative to one another in acquiring T sets of measurement data. The system may be used in projection imaging and/or CT imaging. Processed image data, such as a CT reconstructed image, may be decomposed onto basis functions for analytical processing of multispectral image data to facilitate computer assisted diagnostics. The system may perform this diagnostic function in medical applications and/or security applications.

A source and/or method of generating quantum-correlated and/or entangled photon pairs using parametric fluorescence in a fiber Sagnac loop. The photon pairs are generated in the 1550 nm fiber-optic communication band and detected by a detection system including InGaAs/InP avalanche photodiodes operating in a gated Geiger mode. A generation rate>10³ pairs/s is observed, a rate limited only by available detection electronics. The nonclassical nature of the photon correlations in the pairs is demonstrated. This source, given its spectral properties and robustness, is well suited for use in fiber-optic quantum communication and cryptography networks. The detection system also provides high rate of photon counting with negligible after pulsing and associated high quantum efficiency and also low dark count rate.

A medical diagnostic instrument, such as a colposcope for examining cervical tissue, includes a light source comprising an annular array of high intensity light emitting diodes (LEDs). The LED array includes a central access opening which provides viewing access for the colposcope optical components to the illumination site. The array includes a plurality of sets of LEDs, with each set including a red, blue and green emitting LED. The intensities of the red, blue and green LEDs, respectively, are controllable with a controller to continuously vary or tune the spectral characteristics of the illumination from the light source. Selected color mixes can be stored in a memory for later retrieval.

An imaging apparatus includes: a first pixel which receives both visible light and infrared light, and a second pixel which receives infrared light, both pixels being formed on an imaging device; an infrared light component estimation unit which estimates, based on spectral characteristics of light received by the first pixel and spectral characteristics of light received by the second pixel, a magnitude of an infrared light component contained in a signal outputted from the first pixel from a signal outputted from the second pixel; and a subtraction unit which subtracts the estimated infrared light component from the signal outputted from the first pixel.

A lighting apparatus that provides general lighting in a region or area intended to be occupied by a person includes a source of light of a first spectral characteristic of sufficient light intensity for the lighting application as well as a reflector or a diffusely reflective chamber or cavity having a transmissive optical passage. An exemplary lighting fixture of the type disclosed herein also includes a liquid containing quantum dots. Various containers, locations and positions for the liquid are disclosed. The quantum dots provide a wavelength shift of at least some light to produce a desired second color characteristic in the light output.

A method for specifying pulse characteristics applies codes having pre-defined characteristics to a layout. The layout can be sequentially subdivided into at least first and second components that have the same or different sizes. The method applies a first code having first pre-defined properties to the first component and a second code having second pre-defined properties to the second component. The pre-defined properties may relate to the auto-correlation property, the cross-correlation property, and spectral properties, as examples. The codes can be used to specify subcomponents within a frame, and characteristic values (range-based, or discrete) within the subcomponents.

An optical thin film can have a refractive index variation along a dimension that is perpendicular to its thickness. Two areas that have equal physical thicknesses can have different optical thicknesses. Including the thin film as a layer in a thin film optical filter can provide a corresponding variation in the filter's spectral properties. Dosing an optical thin film with ultraviolet light can cause the refractive index variation. Subjecting the film to hydrogen can increase the refractive index's response to the dose of light. Dosing a region of a thin film optical filter with ultraviolet light can change the spectral properties of the region, for example shifting an out-of-specification optical filter into specification thereby increasing manufacturing yield. An agent can promote the film's response to the dose.

A light source estimation method of this invention estimates from the sensor response the color characteristics of an unknown light source of an image-pickup scene, in order to improve white balance adjustment and other aspects of the quality of color reproduction; a projection conversion portion 6 projects sensor response values 5 into an image distribution 9 in an evaluation space not dependent on the image-pickup light source 2 using parameters obtained by operations which can be calorimetrically approximated from spectral sensitivity characteristics of image-pickup unit 4, which are known, and from spectral characteristics of an assumed test light source 1; an evaluation portion 10 evaluates the correctness of a plurality of the test light sources 1 based on the distribution state of sample values of the projected scene; and accordingly, the correct image-pickup light source 2 is estimated.

An endoscope device obtains tissue information of a desired depth near the tissue surface. A xenon lamp (11) in a light source (4) emits illumination light. A diaphragm (13) controls a quantity of the light that reaches a rotating filter. The rotating filter has an outer sector with a first filter set, and an inner sector with a second filter set. The first filter set outputs frame sequence light having overlapping spectral properties suitable for color reproduction, while the second filter set outputs narrow-band frame sequence light having discrete spectral properties enabling extraction of desired deep tissue information. A condenser lens (16) collects the frame sequence light coming through the rotating filter onto the incident face of a light guide (15). The diaphragm controls the amount of the light reaching the filter depending on which filter set is selected.

A spectral characteristic obtaining apparatus including a light irradiation unit configured to emit light onto a reading object; a spectroscopic unit configured to separate at least a part of diffused reflected light from the light emitted onto the reading object by the light irradiation unit into a spectrum; and a light receiving unit configured to receive the diffused reflected light separated into the spectrum by the spectroscopic unit and to obtain a spectral characteristic. In at least one example embodiment, the light receiving unit is configured to be a spectroscopic sensor array including plural spectroscopic sensors arranged in a direction, and the spectroscopic sensors include a predetermined number of pixels arranged in the direction to receive lights with different spectral characteristics from each other.

A method and system for determination and mapping the quantity of chromophores having a distinct spectrum attached to moving objects in an spectrally rich environment that may include multiple chromophores attached to stationary objects. An area of inters is imaged at different times and different wavelengths, and the spectral properties of the or more chromophores attached to the moving objects are separated from the stationary spectral properties of the background, followed by spectral analysis of the moving objects to determine their quantity. Application to the retinal vasculature is illustrated, showing the imaging, analyzing and quantifying of the oxygen saturation of retinal blood, resolved for the different vascular compartments—capillaries, arterioles, venules, arteries, and veins. Changes in the structure of the vascular environment are also determined, whether growth of new vessels or the elimination of existing ones, by the generation of path maps based on analysis of differential images taken at a single wavelength of the moving components in the blood flow.

An image pickup apparatus comprising an optical element which absorbs rays having specific wavelengths, an optical element which reflects rays having specific wavelengths and an organic color mosaic filter, wherein a total spectral characteristic of the optical elements satisfies the following condition:

0.45≦|ΔT/ΔW|≦0.75.