An HDR Spectral Imaging System for Time-Varying Omnidirectional Scene

Abstract

Omnidirectional spectral imaging technology is crucial in many fields including computer vision and image analysis. It should be noted that the dynamic range of luminance values in natural scenes is quite large, and the scenes are timevarying since objects and light sources change dynamically. This paper proposes a system for acquiring high dynamic range (HDR) spectral images for time-varying omnidirectional natural scenes. The system is constructed using two programmable highspeed video cameras with wide angle lenses and a programmable rotating table. Two different types of color filters are mounted on the two color video cameras for six band image acquisition. We present several algorithms for HDR image synthesis, lens distortion correction, image registration, and omnidirectional image synthesis. Spectral power distributions of illuminants (color signals) are recovered from the captured six-band images based on the Wiener estimation algorithm. The performances of the proposed system are discussed in detail in terms of the system configurations, acquisition time, artifacts, and spectral estimation accuracy. Experimental results in actual scenes show that the proposed system is feasible and powerful for acquiring HDR spectral images of time-varying omnidirectional scenes.

Configuration and Registration of Multi-Camera Spectral Image Database of Icon Paintings

“…Several feature-based and intensity-based registration techniques for spectral images have been proposed [19][20][21][22][23][24] in the literature. Two source of misalignment exist in spectral image cubes: (1) the geometrical distortion due to the difference in the optical path of the channels (e.g., in multi-sensor design) or the non-coplanar placement of filters (e.g., in filter wheel design); and (2) the chromatic aberration due to the dependence of lens magnification and refraction index on wavelength.…”