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This paper presents an analytic method for synthetic-aperture inversion when the measurements are corrupted with noise and clutter. We use microlocal analysis in a statistical setting to develop filtered-backprojection-type reconstruction methods. The inversion method is applicable in non-ideal scenarios, such as those involving arbitrary source… (More)

- Birsen Yazıcı, Gerald B Kliman
- 1999

— It is well known that motor current is a nonsta-tionary signal, the properties of which vary with respect to the time-varying normal operating conditions of the motor. As a result, Fourier analysis makes it difficult to recognize fault conditions from the normal operating conditions of the motor. Time–frequency analysis, on the other hand, unambiguously… (More)

- Ling Wang, Evren Yarman, Birsen Yazıcı
- 2008

We consider passive airborne receivers that use backscattered signals from sources of opportunity transmitting fixed-frequency waveforms, which we refer to as Doppler Synthetic Aperture Hitchhiker (DSAH). We present a novel image formation method for DSAH. Our method first correlates the windowed signal obtained from one receiver with the windowed,… (More)

We derive a new image reconstruction method for distributed apertures operating in complex environments. The aperture elements can be distributed spatially in an arbitrary fashion, can be several hundred wavelengths apart, and can involve transmission from multiple elements simultaneously. Moreover, the object to be imaged can be either in the near-field or… (More)

We develop a new passive image formation method capable of exploiting information about multiple scattering in the environment, as well as statistics of the objects to be imaged, additive noise and clutter, using measurements from a sparse array of receivers that rely on illumination sources of opportunity. The array of receivers can be distributed… (More)

Diffuse optical tomography (DOT) in the near infrared involves the reconstruction of spatially varying optical properties of a turbid medium from boundary measurements based on a forward model of photon propagation. Due to the nonlinear nature of DOT, high quality image reconstruction is a computationally demanding problem which requires repeated use of… (More)

In this work, we present spatially resolved pharmacokinetic rate images of indocyanine green (ICG) obtained from three breast cancer patients using near infrared imaging methods. We used a two-compartment model, namely, plasma and extracellular extravascular (EES), to model ICG kinetics around the tumor region. We introduced extended Kalman filtering (EKF)… (More)

We derive an optimal transmit waveform for filtered backprojection-based synthetic-aperture imaging. The waveform is optimal in terms of min-imising the mean square error (MSE) in the resulting image. Our optimization is performed in two steps: First, we consider the minimum-mean-square-error (MMSE) for an arbitrary but fixed waveform, and derive the… (More)

— In this paper we present an analytic filtered-backpropagation inversion method for radar imaging when the transmitters and receivers are moving along independent flight paths. The flight paths are arbitrary, but assumed known. We assume a single-scattering model for the radar data, and we assume that the ground topography is known. We assume, in addition,… (More)

- Ling Wang, Birsen Yazıcı
- 2011

We present a novel passive image formation method for moving targets using distributed apertures capable of exploiting information about multiple-scattering in the environment. We assume that the environment is illuminated by non-cooperative transmitters of opportunity with unknown location and unknown transmitted waveforms. We develop a passive measurement… (More)