A thermal imaging system has been demonstrated, which uses wavefront coding to provide an extended depth of field. Aberrations are introduced into the optical system, which are optimised to be insensitive to defocus; a single image processing algorithm can be successfully applied to images with a range of focus errors. This requires both the design of the wavefront coding surface and the implementation of efficient and effective image processing electronics. The design of the freeform wavefront coding surface goes hand-in-hand with that of the electronics architecture. An optimised decoding algorithm is implemented in the image processing electronics to achieve real-time imaging performance.Keywords: Wavefront coding, extended depth of focus, extended depth of field, computational imaging.

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Previous research in hybrid imaging tends to have emphasized constancy of the modulation transfer function and ignored the significant variations in the phase-transfer function. We show that the aberrations introduced by phase mismatch effects can also be the key to deducing the PSF and that when this is consequently allowed to vary an overall improvement in image quality can be attained.

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