Abstract: Disclosed are systems are methods for identifying the composition of single aerosol particles, particularly that of bioaerosol particles. A continuous timing laser tightly coupled with a pulse ionization laser is used to index aerosol particles, measure particle properties, and trigger the ionization laser to fire when each particle enters the beam of the trigger laser. Ionized fragments and optionally photons produced when each particle is struck by the ionization laser are analyzed using one or more detectors including a TOF-MS detector and an optical detector. Individual single particle spectra are aligned and denoised prior to averaging.

Abstract: Aspects of the invention are directed to systems and methods for generating spectral computed tomography data for spectral X-ray image reconstruction using of pixelated k-edge apertures. A method is provided for generating a spectral computed tomography. The method includes the steps of generating a plurality of X-ray beams; encoding the plurality of X-ray beams by transmitting the plurality of beams through a pixelated K-edge coded aperture structure; detecting the encoded plurality of X-ray beams; and reconstructing a spectral CT image from the encoded plurality of X-ray beams.

Abstract: Aspects of the invention are directed to systems and methods for generating spectral computed tomography data for spectral X-ray image reconstruction using of pixelated k-edge apertures. A method is provided for generating a spectral computed tomography. The method includes the steps of generating a plurality of X-ray beams; encoding the plurality of X-ray beams by transmitting the plurality of beams through a pixelated K-edge coded aperture structure; detecting the encoded plurality of X-ray beams; and reconstructing a spectral CT image from the encoded plurality of X-ray beams.

Abstract: Aspects of the invention are directed to systems and methods for generating spectral computed tomography data for spectral X-ray image reconstruction using of pixelated k-edge apertures. A method is provided for generating a spectral computed tomography. The method includes the steps of generating a plurality of X-ray beams; encoding the plurality of X-ray beams by transmitting the plurality of beams through a pixelated K-edge coded aperture structure; detecting the encoded plurality of X-ray beams; and reconstructing a spectral CT image from the encoded plurality of X-ray beams.

Abstract: Aspects of the invention are directed to systems and methods for generating spectral computed tomography data for spectral X-ray image reconstruction using of pixelated k-edge apertures. A method is provided for generating a spectral computed tomography. The method includes the steps of generating a plurality of X-ray beams; encoding the plurality of X-ray beams by transmitting the plurality of beams through a pixelated K-edge coded aperture structure; detecting the encoded plurality of X-ray beams; and reconstructing a spectral CT image from the encoded plurality of X-ray beams.

Abstract: Spectral imaging sensors and methods are disclosed. A spectral imaging sensor includes a color-coded array of apertures positioned to receive light from an object to be imaged. The array includes a first plurality of apertures configured to pass light in a first predetermined wavelength range and a second plurality of apertures configured to pass light in a second predetermined wavelength range different from the first predetermined wavelength range. The imaging sensor further includes one or more optical elements positioned to receive light passing through the color-coded array, and a photodetector positioned to receive light from the one of more optical elements. A spectral imaging method includes the steps of filtering light from an object to be imaged through a color-coded array of apertures, redirecting the filtered light with one or more optical elements, and receiving the redirected light with a photodetector.

Abstract: Spectral imaging sensors and methods are disclosed. A spectral imaging sensor includes a color-coded array of apertures positioned to receive light from an object to be imaged. The array includes a first plurality of apertures configured to pass light in a first predetermined wavelength range and a second plurality of apertures configured to pass light in a second predetermined wavelength range different from the first predetermined wavelength range. The imaging sensor further includes one or more optical elements positioned to receive light passing through the color-coded array, and a photodetector positioned to receive light from the one of more optical elements. A spectral imaging method includes the steps of filtering light from an object to be imaged through a color-coded array of apertures, redirecting the filtered light with one or more optical elements, and receiving the redirected light with a photodetector.

Abstract: A method of reducing noise in a sequence of digital video frames is performed by motion estimation between a current noisy frame and a previous noise-reduced frame, to generate motion vectors indicating relative motion between the pixels in the current noisy frame and the corresponding pixels in the previous noise-reduced frame; and removing noise from the current noisy frame by computing the weighted average of pixels in the current noise frame and the corresponding pixels in the previous noise-reduced frame based on the motion vectors, to generate a noise-reduced output frame.

Abstract: A method of generating a authentication code (“MAC”) with improved error tolerance exhibits improved survivability against acceptable signal distortions such as recompression. A method of generating a message authentication code associated with an image includes receiving blocks of image coefficient data where each coefficient has an original value falling within a range of values. The range of values is divided into first and second regions both having allowed coefficient values, and an error tolerance buffer region formed between the first and second regions having disallowed coefficient values. The original values of DC coefficients from each block of the image coefficient data is mapped to a modified value contained in one of the first and second regions, but not contained in the error tolerance buffer region. A MAC is generated as a function of the most significant bits of the modified image coefficient values.

Abstract: According to the principles of the invention, there is provided a system for generating a message authentication code for a conventional digital video stream. The system operates on the rows and columns of block data for a video stream, and more specifically on histograms of DC coefficients from each row and column, to produce a compact code that is nonetheless descriptive of the underlying images in the video stream. The message authentication code can be reproduced from the images of a received video stream, and if desired, compared with a digital watermark embedded in the video stream in order to confirm the accuracy of the video content or identify the source of the video stream.

Abstract: A system (100) for watermarking digital data includes a watermark etching subsystem (105) and a watermark extraction subsystem (110). The watermark etching subsystem (105) obtains a matrix of digital data values, selects windows including a plurality of data values from the matrix, specifies a parameter that indicates an acceptable amount of variation in the data values, and etches watermark bits in each window of data values using the specified parameter. The watermark extraction subsystem (110) obtains a matrix of digital data values containing an etched watermark, selects windows comprising a plurality of data values from the matrix, and extracts watermark bits from each window of data values using the specified parameter.