Multichanneled finite-conjugate imaging

Abstract

Multichanneled imaging systems rely on nonredundant images recorded by an array of low-resolution imagers to enable construction of a high-resolution image. We show how the varying degree of redundancy associated with imaging throughout the imaged volume effects image quality. Using ray-traced image simulations and a metric used as a proxy for human perception, we show that robust recovery of high-resolution images can be obtained by avoiding excessive redundancy and that this is a felicitous consequence of typical manufacturing tolerances.

Compact multi-aperture imaging with high angular resolution

“…The sampling phase and redundancy varies with range and at certain ranges there could, for a perfectly manufactured system, be significant redundancy between channels and super-resolution would be ineffective. In practice however, typical manufacturing tolerances tend to randomize sampling phase, maintaining the effectiveness of super-resolution with range [8]. On the second issue; the N-fold reduction in width of a lens aperture also reduces the diffraction-limited angular resolution by a factor N and thus MA imaging can maintain the angular resolution of a single-aperture imaging system only for small N. MA imaging have previously been used to improve compactness, but its application has been restricted to low-angular resolution imaging [2][3][4][5][6].…”

Time-sequential pipelined imaging with wavefront coding and super resolution

“…Generally, when the imager is handheld there is randomised motion between the imager and the scene, requiring frame-to-frame co-registration. In addition, this movement will tend to randomise the sampling phase of the scene by the detector array thus enabling a highquality super-resolution image to be computed from the video frame sequence [7][8][9]. The video frames in figure 2 were recorded using a LWIR camera, figures 2(a), 2(b), and 2(c) are compared to show the gradual improvement of the wavefront coded images -2(b) and (c) -to the initial image without a phase mask in the pupil plane.…”

Super-resolution imaging using a camera array

“…Small, random variations in sampling offset, as occur with typical manufacturing tolerances for assembly of the camera array, tend to decohere the effects of varying redundancy across the array yielding an image quality that is approximately invariant with range and yields an image quality that is almost as high as a perfectly aligned array with zero redundancy [8].…”

“…In practice, the resolution increase is also determined by registration accuracy, optical aberrations, and degree of nonredundancy [8]. We consider now how experimentally determined image quality varies with increasing numbers of cameras.…”

“…This appears to be limited by suppression of the MTF by the pixel response and optical aberrations of the low-cost COTS cameras, which in turn reduce registration accuracy. Improved SR, approaching the diffraction limit of the individual cameras [8], will require detectors with higher signal-to-noise ratios and lower aberration optics enabling also an associated improvement in image co-registration. This SR factor provides scope for a commensurate reduction in lens track length.…”