Wide field of view optical module for linear sensor

1. A sensing module comprising:

a linear image sensor; and

an optical unit comprising:

an optical element having a curved surface; and

a covering on a flat outward surface of said optical element, said covering having a slit formed therein,

said optical unit facing said sensor with said slit perpendicular to a longitudinal axis of said linear sensor and to image a wide field of view onto a single pixel of said linear sensor, wherein light impinging normal to said slit, at any location along said slit, is imaged on a single central pixel of said linear sensor while light impinging at one of a plurality of non-normal angles to said slit at any location along said slit, is imaged on an associated one of a plurality of non-central pixels of said linear sensor,

wherein said optical element is a freeform lens comprising:

an aspheric optical surface with variable optical power located on an inward surface of said lens facing said sensor, wherein said surface focuses light incident on said slit at each vertical elevation angle across a linear sensor and wherein the optical power of said lens varies to maintain a constant magnification.

2. The sensing module of claim 1 and wherein said optical element is a single monolithic lens.

3. The sensing module of claim 2 and wherein a magnification of said optical element is varied to map a plurality of vertical lines to each one of said pixels of said linear sensor with minimal distortion.