Embodiments of the present invention can resolve molecules beyond the optical diffraction limit in three dimensions. A double-helix point spread function can be used to in conjunction with a microscope to provide dual-lobed images of a molecule. Based on the rotation of the dual-lobed image, the axial position of the molecule can be estimated or determined. In some embodiments, the angular rotation of the dual-lobed imaged can be determined using a centroid fit calculation or by finding the midpoints of the centers of the two lobes. Regardless of the technique, the correspondence between the rotation and axial position can be utilized. A double-helix point spread function can also be used to determine the lateral positions of molecules and hence their three-dimensional location.

https://www.pnas.org/content/pnas/106/9/2995.full.pdf

Three-dimensional single-molecule fluorescence imaging beyond the diffraction limit using a double-helix point spread function

A portable ultrasound imaging system includes a scan head coupled by a cable to a portable battery-powered data processor and display unit. The scan head enclosure houses an array of ultrasonic transducers and the circuitry associated therewith, including pulse synchronizer circuitry used in the transmit mode for transmission of ultrasonic pulses and beam forming circuitry used in the receive mode to dynamically focus reflected ultrasonic signals returning from the region of interest being imaged.

Portable ultrasound imaging system

Methods for improving the availability of information derived from signals received from an object irradiated with coherent pulses of any form of radiation that exhibits a wave nature are disclosed. A method for reducing speckle derives separate component noncoherent signals from the received signals, and combines these separate noncoherent signals to form improved composite noncoherent signals. Weighting and processing of component signals can be applied as a function of time, frequency, and signal amplitude to optimize speckle reduction in all or a critical part of the signal by compensating for the range and frequency dependence of attenuation and the frequency dependence of scattering phenomena. In a method for enhancing resolution, separate component coherent signals are derived from the received signals, weighted and processed, and combined to form improved composite coherent signals; then noncoherent signals are derived from the improved composite coherent signals. In both methods, signals can be processed either in the analog or digital domains or in hybrid analog/digital domains. The apparatus for performing each method also is disclosed.

Frequency diversity for image enhancement

Portable ultrasound imaging data

A method and an apparatus are provided for dynamic, real-time adaptive focusing for ultrasound imaging. Aberration delay correction values, corresponding to an aberration region in an imaged subject, are measured concurrently during B-mode imaging scan lines and updated at the scan line rate. The measured aberration delay correction values are then applied concurrently to correct the focus of all transmitted and received ultrasound scan lines, regardless of the imaging mode, scan geometry, or imaging frequencies.

Method and apparatus for real-time, concurrent adaptive focusing in an ultrasound beamformer imaging system

An ultrasonic imaging system (50) has a means (70) connected to compare the signals received by the transducer elements (54-1 through 54-21). A means (130) is connected to inhibit or otherwise modify gain of selected ones of the signals based on the comparison to reduce multipath ultrasonic wave interference, refraction or obstruction image distortion or degradation. A transducer array (52) is formed as sectors of circles with substantially equal arc lengths. A digital signal processing circuit for the system (50) has a plurality of dual port RAMs (66-1 through 66-21) as delay lines and a cross-correlation means (70) including output addressing circuit (130) controlled by a microcomputer (128). The output addressing circuit (130) generates addresses for output of information from the dual port RAM delay lines (66-1 through 66-21) to accomplish time delay correction and elimination or other gain interference, refraction or obstruction.

Ramsey Stevens David

Papers

Ultrasonic imaging system with correction for velocity inhomogeneity and multipath interference, using an ultrasonic imaging array