Self-stabilizing image scanner

Claim 2

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor, said multi-faceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 3

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror such that said optical axis is substantially coincident with the spin axis of said rotor; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 4

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror such that said optical axis is substantially coincident with the spin axis of said rotor; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 5

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; optical means for directing energy received from said field of view to said multi-faceted scan mirror whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 6

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; optical means for directing energy received from said field of view to said multi-faceted scan mirror whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 7

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror element such that it occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 8

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror element such that it occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 9

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of the received energy; means for positioning said mirror element such that it occupies different positions during different revolution cycles of said rotor so as to cause interlaced fields of said field of view to be scanned; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 10

A scanner adapted for being gimbal mounted, for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gyroscope adapted for being gimbal mounted, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of the received energy; means for positioning said mirror element such that it occupies different positions during different revolution cycles of said rotor so as to cause interlaced fields of said field of view to be scanned; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 11

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; said multi-faceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 12

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; said multi-faceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 13

The self-stabilizing scanner of claim 6 including a mirror element disposed in the path of the received energy; and means for positioning said mirror element such that it occupies different positions during different revolution cycles of said rotor so as to cause interlaced fields of said field of view to be scanned.

Claim 14

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror elements such that is occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 15

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror elements such that is occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 16

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly having a gimbal support structure, and an inner gimbal and an outer gimbal mounted on said support structure such that said inner gimbal has at least two degrees of freedom of movement; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means being mounted on said inner gimbal so as to cause said optical axis to be substantially coincident with the spin axis of said rotor; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 17

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly having a gimbal support structure, and an inner gimbal and an outer gimbal mounted on said support structure such that said inner gimbal has at least two degrees of freedom of movement; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means being mounted on said inner gimbal so as to cause said optical axis to be substantially coincident with the spin axis of said rotor; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 18

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror said first optical means including temperature compensator means for reducing focus errors due to temperature changes; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 19

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor; a multi-faceted scan mirror disposed for rotation with said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror said first optical means including temperature compensator means for reducing focus errors due to temperature changes; detector means for providing electrical signals representative of the relative intensity of energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 20

The self-stabilizing image scanner of claim 10 wherein said second optical means includes temperature compensator means for reducing focus errors due to temperature changes.

Claim 21

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multifaceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; optical means for directing energy received from said field of view to said multi-faceted scan mirror whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 22

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multifaceted scan mirror having mirror facets which make various angles with the spin axis of said rotor; optical means for directing energy received from said field of view to said multi-faceted scan mirror whereby as said rotor revolves the field of view is scanned in a two-dimensional pattern; detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 23

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror element such that it occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 24

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror element such that it occupies different positions during periods different ones of said mirror facets are illuminated by said received energy, whereby the field of view is scanned in a two-dimensional pattern; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 25

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly having a gimbal support structure, and an inner gimbal and an outer gimbal mounted on said support structure such that said inner gimbal has at least two degrees of freedom of movement; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror, said optical means being mounted on said inner gimbal so as to cause said optical axis to be substantially coincident with the spin axis of said rotor; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 26

A self-stabilizing scanner for providing electrical signals representative of the relative energy distribution within a field of view encompassing an optical axis, said scanner comprising: a gimbal assembly having a gimbal support structure, and an inner gimbal and an outer gimbal mounted on said support structure such that said inner gimbal has at least two degrees of freedom of movement; a gyroscope mounted on said gimbal assembly, said gyroscope having a rotor, and said rotor carrying a multi-faceted scan mirror; optical means for directing energy received from said field of view to said multi-faceted scan mirror, said optical means being mounted on said inner gimbal so as to cause said optical axis to be substantially coincident with the spin axis of said rotor; and detector means disposed to intercept a portion of the energy reflected from said multi-faceted scan mirror, for providing electrical signals representative of the relative intensity of said intercepted energy; whereby as said rotor revolves stabilization of said optical axis is provided and said detector means provides electrical signals representative of the relative energy distribution along at least one dimension of said field of view.

Claim 27

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which emcompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means being mounted on said inner gimbal so as to cause said optical axis and the spin axis of said rotor to be substantially coincident; detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.

Claim 28

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which emcompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means being mounted on said inner gimbal so as to cause said optical axis and the spin axis of said rotor to be substantially coincident; detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.

Claim 29

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which encompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure, and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said mutli-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror elements such that it occupies different positions during different revolution cycles of said rotor so as to cause interlaced field of said field of view to be scanned; detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.

Claim 30

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which encompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure, and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said mutli-faceted scan mirror; a mirror element disposed in the path of said received energy; means for positioning said mirror elements such that it occupies different positions during different revolution cycles of said rotor so as to cause interlaced field of said field of view to be scanned; detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.

Claim 31

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which encompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure, and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means including temperature compensator means for reducing focus errors due to temperature changes. detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means, said second optical means including temperature compensator means for reducing focus errors due to temperature changes; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.

Claim 32

A self-stabilizing image scanner for providing electrical signals representative of the thermal energy distribution within a field of view which encompasses an optical axis, said image scanner comprising: a gimbal assembly having a gimbal support structure, and inner and outer gimbal members mounted on said support structure such that said inner gimbal member has two degrees of freedom of movement; a gyroscope mounted on said inner gimbal member, said gyroscope having a stator, and a rotor adapted for rotation about said stator; said rotor carrying a multi-faceted scan mirror thereon and said mirror facets making various angles with the spin axis of said rotor; first optical means for directing energy received from said field of view to said multi-faceted scan mirror, said first optical means including temperature compensator means for reducing focus errors due to temperature changes. detector means for providing electrical signals representative of the relative intensity of thermal energy applied thereto; and second optical means for directing energy reflected from said multi-faceted scan mirror to said detector means, said second optical means including temperature compensator means for reducing focus errors due to temperature changes; whereby as said rotor revolves said detector means provides electrical output signals representative of the relative thermal energy distribution within said field of view, and the angular momentum of said rotor provides spatial stabilization of said optical axis.