84 results about "Phase diversity" patented technology

A geometric measurement system is adapted to precisely measure one or more surfaces of objects such as corneas, molds, contact lenses in molds, contact lenses, or other objects in a fixture. The geometric measurement system can employ one or more of three possible methods of measurement: Shack-Hartmann wavefront sensing with wavefront stitching; phase diversity sensing; and white light interferometry.

The invention provides an image super-resolution and image quality enhancement method and relates to the technical field of digital image processing in a space remote sensing imaging system. The image super-resolution and image quality enhancement method solves the problems that optimization elements which can be utilized are less, the improvement space of the image quality is limited, and accordingly the image quality cannot be effectively improved in the existing Wiener filtering image restoration method. The image super-resolution and image quality enhancement method comprises utilizing a light beam splitter to collect in-focus images and out-of-focus images in two channels respectively and collect N staggered in-focus images which enable 1 / N pixels to be staggered in the horizontal and vertical direction relative to the in-focus images; performing PD (Phase Diversity) processing on the in-focus images and the out-of-focus images; utilizing a conjugate gradient algorithm to obtain an aberration coefficient; obtaining restored target images after the PD processing and calculating an objective function; performing Wiener filtering processing on the staggered in-focus images and the restored target images; and performing sub-pixel integration on the two restored images to obtain a restored image with ultrahigh resolution. The image super-resolution and image quality enhancement method achieves super-resolution and high definition of images and improves the resolution by 1.4 times.

Systems, including apparatus and methods, for obtaining and / or correcting images, particularly from atmospheric and / or other distortions. These corrections may involve, among others, determining corrective information in a first (e.g., visible) wavelength regime, and then applying the corrective information in a second (e.g., longer) wavelength regime, such as infrared (IR) or millimeter-wave (MMW) wavelengths, in real time or with post-processing. For example, these corrections may include scaling a phase diversity correction from one wavelength to another. These systems may be useful in any suitable imaging context, including navigation, targeting, search and rescue, law enforcement, and / or surveillance, among others.

A system capable of determining wavefront characteristics, such as air induced wavefront aberrations, includes a field programmable gate array (FPGA) device executing a phase diversity algorithm. The FPGA device can be a stand-alone device or comprise multiple FPGAs. The device receives an “in-focus” and an “out-of-focus” image having a known optical difference from that of the “in-focus” image. The device then performs as many phase diversity algorithm iterations as desired to reach an expression for the wavefront aberrations induced on the collected image data. The resulting wavefront data may be used to produce an enhanced image of the original image data. Example applications include remote sensors and targeting systems, and both passive imaging and active projection systems that compensate for wavefront anomalies.

An electric field waveform of an optical signal is precisely measured with high time resolution. Particularly, determination of inter-symbol interference has been difficult. Output light from the laser source is divided into first and second portions. The first portion is modulated by an optical modulator. The second portion is delayed by a delay line for the same quantity of delay as that of the first portion. The first and second portions are fed to a phase diversity circuit to configure a homodyne interferometer. An optical input sampling oscilloscope stabilizes a variable optical phase shifter to set an optical phase at a particular point of time to a fixed value using a pattern sync signal as a reference. An optical input sampling oscilloscope repeatedly averages optical waveforms and a CPU conducts three-dimensional display of the optical electric field waveform from which noise has been removed.

In one embodiment, a method for performing antenna diversity combining for digitally broadcast radio signals includes generating a first signal quality metric for a first signal obtained from an incoming digitally broadcast radio signal received in a first signal path, and similarly generating a second signal quality metric for a second signal obtained from the radio signal received in a second signal path. Then the first and second signals from these paths can be coherently combined based on the signal quality metrics to obtain a combined frequency domain symbol. In some embodiments, this combined frequency domain symbol may be remodulated to a time domain symbol. Also in some embodiments N tuners can be daisy chained to generate a final output that is either a frequency domain symbol of combined sub-carriers, soft bits to a forward error correction (FEC) decoder, or a remodulated time domain symbol. As a further possibility, each of the N tuners can use a different local oscillator (LO) frequency.

The present invention discloses a method and an apparatus for measuring quality parameters of optical transmission channels. The apparatus comprises: a tunable optical filter for receiving an optical signal, performing wavelength or optical carrier demultiplexing on the optical signal, and out-of-band ASE noise suppression; an optical coherent receiver connected to the tunable optical filter, for performing polarization- and phase-diversity detection on the filtered optical signal and converting it into multiple lane baseband electrical signals; analog-to-digital converters for sampling and quantizing the multiple lane baseband electrical signals so as to convert the them into multiple lane digital signals; a digital signal processing module for processing the multiple lane digital signals to obtain quality parameters; and an display module for displaying the quality parameters. By the device according to an embodiment of the invention, real-time measurement of various key performance parameters of the 40 Gbps, 100 Gbps and extra-100 Gbps (for example, 200 Gbps, 400 Gbps and 1 Tbps) coherent polarization-multiplexed system is achieved simultaneously, especially the issue of real-time measurement of the in-service in-band OSNR is solved. Therefore, the network operation and maintenance are facilitated and the cost of network operation and maintenance is saved.