Imaging apparatus

Claim 1

An apparatus for producing a visible image of a scene by sensing non-visible radiation from the scene, said apparatus comprising: a mirror assembly which is rotatable about an axis, said assembly comprising a number, n, of planar mirrors disposed equiangularly around the periphery thereof, each planar mirror subtending a different tilt angle with respect to the axis, a cross-section through the mirror assembly in a plane perpendicular to the axis taking the shape of a regular polygon; an objective lens arranged to receive radiation from the scene after the radiation is reflected by a planar mirror which is at a scanning location, said lens having a focal length; a linear array of radiation-sensitive detectors arranged to receive radiation from the scene which is reflected by a planar mirror at the scanning location and which passes through the objective lens, said array having a linear length and an angular length, the angular length being equal to the linear length of the array divided by the focal length of the objective lens; a linear array of light sources arranged to emit light onto a planar mirror at a reconstruction location, each light source being coupled to one corresponding detector of the detector array; and viewing means arranged to receive light reflected by the planar mirror at the reconstruction location from the light sources; characterized in that; the scanning and reconstruction locations are selected such that during rotation of the mirror assembly to move a planar mirror from the scanning location to the reconstruction location, an integral number, x, of planar mirrors pass through the scanning location, the number, x, being chosen such that there is no positive integer, m, less than n where rotation of the mirror assembly to pass mx mirrors through the scan location will terminate with the same mirror at the scan location as the mirror at the scan location at the start of the rotation; and the differences between the tilt angles of the planar mirrors are integral multiples of half of the angular length of the detector array, the differences between the tilt angles of pairs of planar mirrors at the scanning and reconstruction locations, being equal to half the angular length of the detector array for all but one pair of mirrors.

Claim 2

An apparatus for producing a visible image of a scene by sensing non-visible radiation from the scene, said apparatus comprising: a mirror assembly which is rotatable about an axis, said assembly comprising a number, n, of planar mirrors disposed equiangularly around the periphery thereof, each planar mirror subtending a different tilt angle with respect to the axis, a cross-section through the mirror assembly in a plane perpendicular to the axis taking the shape of a regular polygon; an objective lens arranged to receive radiation from the scene after the radiation is reflected by a planar mirror which is at a scanning location, said lens having a focal length; a linear array of radiation-sensitive detectors arranged to receive radiation from the scene which is reflected by a planar mirror at the scanning location and which passes through the objective lens, said array having a linear length and an angular length, the angular length being equal to the linear length of the array divided by the focal length of the objective lens; a linear array of light sources arranged to emit light onto a planar mirror at a reconstruction location, each light source being coupled to one corresponding detector of the detector array; and viewing means arranged to receive light reflected by the planar mirror at the reconstruction location from the light sources; characterized in that; the scanning and reconstruction locations are selected such that during rotation of the mirror assembly to move a planar mirror from the scanning location to the reconstruction location, an integral number, x, of planar mirrors pass through the scanning location, the number, x, being chosen such that there is no positive integer, m, less than n where rotation of the mirror assembly to pass mx mirrors through the scan location will terminate with the same mirror at the scan location as the mirror at the scan location at the start of the rotation; and the differences between the tilt angles of the planar mirrors are integral multiples of half of the angular length of the detector array, the differences between the tilt angles of pairs of planar mirrors at the scanning and reconstruction locations, being equal to half the angular length of the detector array for all but one pair of mirrors.

Claim 5

An apparatus for producing a visible image of a scene by sensing non-visible radiation from the scene, said apparatus comprising; a mirror assembly which is rotatable about an axis, said assembly comprising a number, n, of planar mirrors disposed equiangularly around the periphery thereof, each planar mirror subtending a different tilt angle with respect to the axis, a cross-section through the mirror assembly in a plane perpendicular to the axis taking the shape of a regular polygon; a linear array of radiation-sensitive detectors arranged to receive radiation from the scene which is reflected by a planar mirror at a scanning location; and a linear array of light sources arranged to emit light onto a planar mirror at a reconstruction location, each light source being coupled to one corresponding detector of the detector array; characterized in that the scanning and reconstruction locations are selected such that during rotation of the mirror assembly to move a planar mirror from the scanning location to the reconstruction location, an integral number, x, of planar mirrors pass through the scanning location, the number, x, being chosen such that there is no positive integer, m, less than n where rotation of the mirror assembly to pass mx mirrors through the scan location will terminate with the same mirror at the scan location as the mirror at the scan location at the start of the rotation.

Claim 6

An apparatus for producing a visible image of a scene by sensing non-visible radiation from the scene, said apparatus comprising; a mirror assembly which is rotatable about an axis, said assembly comprising a number, n, of planar mirrors disposed equiangularly around the periphery thereof, each planar mirror subtending a different tilt angle with respect to the axis, a cross-section through the mirror assembly in a plane perpendicular to the axis taking the shape of a regular polygon; a linear array of radiation-sensitive detectors arranged to receive radiation from the scene which is reflected by a planar mirror at a scanning location; and a linear array of light sources arranged to emit light onto a planar mirror at a reconstruction location, each light source being coupled to one corresponding detector of the detector array; characterized in that the scanning and reconstruction locations are selected such that during rotation of the mirror assembly to move a planar mirror from the scanning location to the reconstruction location, an integral number, x, of planar mirrors pass through the scanning location, the number, x, being chosen such that there is no positive integer, m, less than n where rotation of the mirror assembly to pass mx mirrors through the scan location will terminate with the same mirror at the scan location as the mirror at the scan location at the start of the rotation.