Superresolution of Passive Millimeter-Wave Imaging
Abstract
This project develops methods for image acquisition that will provide superresolution capability without the benefit of assumptions about the object intensity distribution. Superresolution is of particular interest in passive millimeter wave imaging, which has tremendous potential for imaging in adverse conditions but suffers from poor resolution. Because of the finite aperture in PMMW, the acquired image is strictly bandlimited. Therefore, an important issue is sampling pattern optimization. Ordinarily, a focal plane sensor array has sensors placed in a rectangular grid pattern at sub-Nyquist density, and the must be dithered to sample the image plane at the Nyquist density in each dimension. However, the Nyquist density oversamples the image due to the usually circular support of the diffraction-limited image spectrum. We have developed an efficient algorithm for optimizing the dithering pattern so that the image can be reconstructed reliably from a less dense periodic nonuniform set of samples, which can be obtained from a dithered rectangular-grid array. The resulting algorithm can be used to explore image acquisition strategies. We have also investigated optimizing the aperture sensitivity to shape the spatial frequency response of the acquisition system. Preliminary results indicate only marginal improvement. However, under certain circumstances, as in the case where edge detection is the primary task for imaging, more significant improvement may be achieved.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2000
- Accession Number
- ADA380875
Entities
People
- Stanley J. Reeves
Organizations
- Auburn University