Abstract: A method and a system for detection and synthetic aperture (SA) imaging of a target are disclosed. The method may include illuminating a scene with a search signal transmitted from a moving platform, receiving a search return signal from a target present in the scene, and estimating, from the search return signal, the range and the angular location of the target. The method may also include generating an SA transmission signal and a local oscillator (LO) signal with a time delay therebetween based on the estimated range, and illuminating the scene with the SA transmission signal pointed along an imaging direction based on the estimated angular location of the target. The method may further include receiving an SA return signal from the target, mixing the SA return signal with the LO signal to generate SA signal data, and generating an SA image of the target from the SA signal data.

Abstract: Methods and systems are for determining the concentration of a chemical species in an analyte solution. At least one train of segments are injected into a microfluidic channel having a first end and a second end, each train of segments having segments of analyte solution and segments of sensing solution which are immiscible with the segments of analyte solution. The train of segments is circulated from the first end to the second end of the microfluidic channel such that a reversible chemical exchange is established between the chemical species of each segment of analyte solution and a chemical indicator of the at least one contacting segment of sensing solution. The response of the chemical indicator is measured at the second end of the microfluidic channel and the concentration of the chemical species in the analyte solution is determined based on the response.

Abstract: A method and a system for detection and synthetic aperture (SA) imaging of a target are disclosed. The method may include illuminating a scene with a search signal transmitted from a moving platform, receiving a search return signal from a target present in the scene, and estimating, from the search return signal, the range and the angular location of the target. The method may also include generating an SA transmission signal and a local oscillator (LO) signal with a time delay therebetween based on the estimated range, and illuminating the scene with the SA transmission signal pointed along an imaging direction based on the estimated angular location of the target. The method may further include receiving an SA return signal from the target, mixing the SA return signal with the LO signal to generate SA signal data, and generating an SA image of the target from the SA signal data.

Abstract: A method and a system are for three-dimensional (3D) synthetic aperture (SA) imaging. The method and system use spatial modulation on SA return signals as a function of their return angle distribution to account for local topography and provide 3D imaging capabilities. In some implementations, the method can involve a step of generating two spatially modulated two-dimensional (2D) SA images of a target region, each of which having a different spatial modulation profile, and a step of combining the two spatially modulated 2D SA images to obtain a 3D SA image. The 3D SA image can be used to determine an elevation map of the target region.

Abstract: A method is for phase-error correction in a synthetic aperture (SA) imaging system. A transmission signal and a local oscillator (LO) signal are generated with a relative time delay, which can be adjusted in real-time to match a range to a target region to be imaged. A portion of the transmission signal is transmitted onto the target region and a return signal is collected and mixed with a portion of the LO signal to provide a raw SA signal. Transmission and LO phase errors associated respectively with the transmission and LO signals are determined, as well as a frequency jitter between the transmission and LO signals. A phase-corrected SA signal is obtained by applying a phase correction to the raw SA signal based on the transmission phase error, the LO phase error and the frequency jitter. An SA imaging system is capable of implementing the method for phase-error correction.

Abstract: Synthetic aperture (SA) imaging methods and systems are assisted by three-dimensional (3D) beam scanning imaging, for example scanning lidar. The methods can include concurrently acquiring an SA image and a 3D scanning image of a target region, determining an elevation map of the target region from the 3D scanning image, and processing the SA image based on the elevation map to provide or enhance 3D imaging capabilities in the SA image. In some implementations, the SA image is a two-dimensional (2D) SA image and the elevation map is used to orthorectify the 2D SA image. In other implementations, the SA image is a phase-wrapped 3D SA image resulting from the combination of two or more 2D SA images and the elevation map is used to perform phase unwrapping on the phase-wrapped 3D SA image.

Abstract: A method and a system are for three-dimensional (3D) synthetic aperture (SA) imaging. The method and system use spatial modulation on SA return signals as a function of their return angle distribution to account for local topography and provide 3D imaging capabilities. In some implementations, the method can involve a step of generating two spatially modulated two-dimensional (2D) SA images of a target region, each of which having a different spatial modulation profile, and a step of combining the two spatially modulated 2D SA images to obtain a 3D SA image. The 3D SA image can be used to determine an elevation map of the target region.

Abstract: Synthetic aperture (SA) imaging methods and systems are assisted by three-dimensional (3D) beam scanning imaging, for example scanning lidar. The methods can include concurrently acquiring an SA image and a 3D scanning image of a target region, determining an elevation map of the target region from the 3D scanning image, and processing the SA image based on the elevation map to provide or enhance 3D imaging capabilities in the SA image. In some implementations, the SA image is a two-dimensional (2D) SA image and the elevation map is used to orthorectify the 2D SA image. In other implementations, the SA image is a phase-wrapped 3D SA image resulting from the combination of two or more 2D SA images and the elevation map is used to perform phase unwrapping on the phase-wrapped 3D SA image.

Abstract: A method is for phase-error correction in a synthetic aperture (SA) imaging system. A transmission signal and a local oscillator (LO) signal are generated with a relative time delay, which can be adjusted in real-time to match a range to a target region to be imaged. A portion of the transmission signal is transmitted onto the target region and a return signal is collected and mixed with a portion of the LO signal to provide a raw SA signal. Transmission and LO phase errors associated respectively with the transmission and LO signals are determined, as well as a frequency jitter between the transmission and LO signals. A phase-corrected SA signal is obtained by applying a phase correction to the raw SA signal based on the transmission phase error, the LO phase error and the frequency jitter. An SA imaging system is capable of implementing the method for phase-error correction.

Abstract: Methods and systems are for determining the concentration of a chemical species in an analyte solution. At least one train of segments are injected into a microfluidic channel having a first end and a second end, each train of segments having segments of analyte solution and segments of sensing solution which are immiscible with the segments of analyte solution. The train of segments is circulated from the first end to the second end of the microfluidic channel such that a reversible chemical exchange is established between the chemical species of each segment of analyte solution and a chemical indicator of the at least one contacting segment of sensing solution. The response of the chemical indicator is measured at the second end of the microfluidic channel and the concentration of the chemical species in the analyte solution is determined based on the response.

Abstract: A method for phase error correction in a synthetic aperture (SA) imaging system is configured to image a target region of a scene from a platform in relative movement with respect to the scene. The method includes acquiring target SA data from the target region and reference SA data from a reference region of the scene, using a SA acquisition unit. One or more phase correction factors are determined from the reference SA data based on an assumption that the reference region has a known topography. The phase correction factors are representative of uncompensated optical-path-length fluctuations along the optical path between the reference region and the SA acquisition unit mounted on the platform. A phase correction is applied to the target SA data based on the phase correction factors so as to obtain phase-corrected target SA data. A SA imaging system implementing the method is also disclosed.

Abstract: A method for phase error correction in a synthetic aperture (SA) imaging system is configured to image a target region of a scene from a platform in relative movement with respect to the scene. The method includes acquiring target SA data from the target region and reference SA data from a reference region of the scene, using a SA acquisition unit. One or more phase correction factors are determined from the reference SA data based on an assumption that the reference region has a known topography. The phase correction factors are representative of uncompensated optical-path-length fluctuations along the optical path between the reference region and the SA acquisition unit mounted on the platform. A phase correction is applied to the target SA data based on the phase correction factors so as to obtain phase-corrected target SA data. A SA imaging system implementing the method is also disclosed.