Pattern correlation optical tracker utilizing circular nutational scanning

Claim 2

In a motion sensing device for producing output signals responsive to the magnitude and direction of the relative movement between the sensing device and a field of view scene comprising signal producing means for producing a signal responsive to the light energy pattern of the scene, storage means for storing said signal as a reference signal, correlator means for correlating said reference signal with a current signal to produce a correlation signal having modulations indicative of said relative movement, and processing means for processing said correlation signal to produce said output signals, the improvement comprising said signal producing means comprising means for producing a signal corresponding to a predetermined nutation of the scene, and including means for storing in said storage means as a reference signal a portion of said signal corresponding to a complete nutational cycle, and further including means for applying to said correlator means a current signal and a reference signal corresponding to the current signal but time delayed with respect to the nutational cycle.

Claim 3

The motion sensing device according to claim 1 wherein said reference signals correspond to a complete circular nutation of the field of view whereby said modulations are indicative of relative movement of said field of view in two dimensions.

Claim 4

The motion sensing device according to claim 2, wherein said signal producing means includes a movable reticle having a predetermined repetitive pattern of light transmitting elements arranged symmetrically about a geometric center for scanning said scene, and light energy sensitive means responsive to the passage of energy through said reticle, said center being offset with respect to the axis of rotation of said reticle to effectively produce an upright circular nutation of said field of view.

Claim 5

The motion sensing device according to claim 1 wherein said reference means is time delayed by one-half of said nutation cycle.

Claim 6

The motion sensing device according to claim 1 wherein said processing means include means for producing a pair of orthogonally related control signals in synchronism with the circular nutation of the field of view so that said output signals correspond to orthogonal components of the relative movement between the sensing device and the scene.

Claim 7

In a motion sensing device for producing output signals responsive to the magnitude and direction of the relative movement between the sensing device and an object within a field of view scene comprising reticle means for repetitively scanning the scene, light energy sensitive means responsive to the radiant energy passing through said reticle means to produce an electrical signal corresponding to the light energy pattern of the current field of view scene, storage means for selectively storing said electrical signal, and signal correlation means having input and output means for producing an output at said output means dependent on local correlation of signals applied to said input means, the improvement comprising said reticle means further comprising means for cyclically nutating the field of view, means for supplying a signal corresponding to a nutational cycle into said storage means to provide a reference signal, means for deriving from said storage means a reference signal corresponding to a current signal but time delayed with respect to the nutational cycle, means for applying said time delayed signal and said current signal to said input means to produce a correlation signal at said output means, and means responsive to said output means including integRation means for producing said output signals.

Claim 8

In a motion sensing device for producing output signals responsive to the magnitude and direction of the relative movement between the sensing device and an object within a field of view scene comprising reticle means for repetitively scanning the scene, light energy sensitive means responsive to the radiant energy passing through said reticle means to produce an electrical signal corresponding to the light energy pattern of the current field of view scene, storage means for selectively storing said electrical signal, and signal correlation means having input and output means for producing an output at said output means dependent on local correlation of signals applied to said input means, the improvement comprising said reticle means further comprising means for cyclically nutating the field of view, means for supplying a signal corresponding to a nutational cycle into said storage means to provide a reference signal, means for deriving from said storage means a reference signal corresponding to a current signal but time delayed with respect to the nutational cycle, means for applying said time delayed signal and said current signal to said input means to produce a correlation signal at said output means, and means responsive to said output means including integRation means for producing said output signals.

Claim 9

The motion sensing device according to claim 6, wherein said nutation of the field of view is a circular nutation.

Claim 10

The motion sensing device according to claim 6 further including means for deriving from said storage means a reference signal corresponding to said current signal and synchronous with respect to the nutational cycle, means for comparing said reference signal and said current signal to produce a comparison signal, and means responsive to a predetermined comparison signal to enter a new signal into said storage means.

Claim 11

In a correlation-type optical tracker comprising a field stop and means for focusing light energy from a selected field of view scene onto said stop, the improvement comprising means for effecting scanning of the scene and simultaneous cyclical nutation of the field of view including rotatable reticle means having a predetermined repetitive pattern of light transmitting elements, at least one repetition of the pattern of elements being offset in relation to another of said repetitions to introduce an effective nutation of the scene, circuit means including light energy responsive means adapted to receive the light energy passing through said elements and converting the same to an electrical waveform responsive to the spatial frequency content of said scene, memory means for storing a waveform representative of at least one complete scan of the scene, means for selectively entering a portion of the waveform into said memory means to provide a reference scene waveform, means for deriving from said memory means a waveform corresponding to a current waveform but time delayed therewith, correlator means for correlating said time delayed reference scene waveform and the waveform corresponding to the current scene to produce a correlation waveform, means responsive to said correlation waveform including integrator means for producing output signals, and control means for controlling the aim of said tracker in response to said integrated signals to maintain said tracker aimed substantially at said scene.

Claim 12

In a correlation-type optical tracker comprising a field stop and means for focusing light energy from a selected field of view scene onto said stop, the improvement comprising means for effecting scanning of the scene and simultaneous cyclical nutation of the field of view including rotatable reticle means having a predetermined repetitive pattern of light transmitting elements, at least one repetition of the pattern of elements being offset in relation to another of said repetitions to introduce an effective nutation of the scene, circuit means including light energy responsive means adapted to receive the light energy passing through said elements and converting the same to an electrical waveform responsive to the spatial frequency content of said scene, memory means for storing a waveform representative of at least one complete scan of the scene, means for selectively entering a portion of the waveform into said memory means to provide a reference scene waveform, means for deriving from said memory means a waveform corresponding to a current waveform but time delayed therewith, correlator means for correlating said time delayed reference scene waveform and the waveform corresponding to the current scene to produce a correlation waveform, means responsive to said correlation waveform including integrator means for producing output signals, and control means for controlling the aim of said tracker in response to said integrated signals to maintain said tracker aimed substantially at said scene.

Claim 13

The tracker according to claim 9, including other correlator means, means for deriving a waveform from said memory means corresponding to said reference scene waveform, means for applying said reference scene waveform and a waveform corresponding to the current scene to said other correlator means to produce a control signal, and memory control means for controlling the entry of a waveform into said memory means in response to a predetermined value of said control signal.

Claim 14

The correlation tracker according to claim 9, wherein said pattern of elements is symmetrical about geometric center, said center being offset with respect to the axis of rotation of said reticle to effectively produce an upright circular nutation of said field of view.

Claim 15

The motion sensing device according to claim 9 including demodulator means responsive to said correlation waveform, said demodulator means including control means responsive to the nutation frequency, for deriving signals responsive to the orthogonal components of movement of the reference scene with respect to the current scene.

Claim 16

The motion sensing device according to claim 9 wherein each repetition of said pattern of elements is arranged in a semirandom order to effect scanning of the scene in other than sequential order.

Claim 17

In a correlation tracker comprising a field stop and means for focusing light energy from a selected field of view scene onto said stop, rotatable reticle means, the improvement comprising said reticle means having a predetermined pattern of apertures having symmetry with respect to a geometric center offset from the center of rotation of the reticle to provide a circular nutation of the field of view, circuit means including light energy responsive means adapted to receive the light energy passing through said apertures to produce an electrical signal responsive thereto, detector means for convertiNg said signal to a waveform responsive to the spatial frequency content of the current scene, memory means for storing a portion of said waveform, means for entering into said memory means a portion of said waveform that corresponds to a nutational cycle, means for deriving from said memory means a portion of said waveform corresponding to a current waveform but time delayed one-half of the nutational cycle, correlator means having input and output circuits for producing an output at said output circuit dependent on local correlation between signals applied to said input circuit, means for applying said delayed waveform and said current waveform from said detector means to said input circuit to produce a correlation waveform at said output circuit, said waveform having modulations substantially corresponding to the relative movement between the scene and the tracker, and means for controlling the aim of said tracker in response to said modulated waveform to maintain the tracker substantially aimed at the scene.

Claim 18

In a correlation tracker comprising a field stop and means for focusing light energy from a selected field of view scene onto said stop, rotatable reticle means, the improvement comprising said reticle means having a predetermined pattern of apertures having symmetry with respect to a geometric center offset from the center of rotation of the reticle to provide a circular nutation of the field of view, circuit means including light energy responsive means adapted to receive the light energy passing through said apertures to produce an electrical signal responsive thereto, detector means for convertiNg said signal to a waveform responsive to the spatial frequency content of the current scene, memory means for storing a portion of said waveform, means for entering into said memory means a portion of said waveform that corresponds to a nutational cycle, means for deriving from said memory means a portion of said waveform corresponding to a current waveform but time delayed one-half of the nutational cycle, correlator means having input and output circuits for producing an output at said output circuit dependent on local correlation between signals applied to said input circuit, means for applying said delayed waveform and said current waveform from said detector means to said input circuit to produce a correlation waveform at said output circuit, said waveform having modulations substantially corresponding to the relative movement between the scene and the tracker, and means for controlling the aim of said tracker in response to said modulated waveform to maintain the tracker substantially aimed at the scene.

Claim 19

The tracker according to claim 14 wherein said detector means includes a zero crossing detector means for converting an incident analog waveform to a binary digital waveform.

Claim 20

The tracker according to claim 15, wherein said memory means includes magnetic recording means rotatable in synchronism with said circular nutation.

Claim 21

The tracker according to claim 15 wherein said first named and said other correlator means include Exclusive-OR circuits, respectively.

Claim 22

The tracker according to claim 14, including means for updating said memory device in response to predetermined conditions including other correlator means having input and output circuits for producing an output at said output circuit dependent on local correlation between signals applied to said input circuit, means for deriving from said memory means a waveform corresponding to a current waveform and applying said derived waveform and said current waveform to said other correlator input circuit and means for controlling the entry of a new waveform into said memory means in response to a predetermined value of the output of said other correlator.

Claim 23

The tracker according to claim 14 wherein the means for controlling the aim of the tracker comprise first and second demodulator means each having an input connected to receive said correlation waveform, demodulator control means responsive to the rotation of said reticle to provide a pair of control signals phase displaced orthogonally from each other respectively for controlling said first and second demodulator means to produce a pair of error signals substantially corresponding to the orthogonal components of the relative movement between the scene and the tracker.

Claim 24

In a correlation-type optical tracker comprising a field stop, means for focusing light energy from a selected field of view scene onto said stop, scanning means for effecting scanning of the scene, circuit means including light energy responsive means adapted to receive the light energy from said scanning means and to convert the same to an analog electrical waveform responsive to the spatial frequency content of said scene, memory means for storing a reference scene waveform, means for selectively entering a portion of said electrical waveform to provide a reference scene waveform, means for deriving said reference waveform from said memory means, correlator means for producing an output dependent on correlation of signals applied to it, means for applying said reference scene waveform and an electrical waveform corresponding to the current scene to said correlator means to produce a correlation waveform having modulations corresponding to the direction and magnitude of relative movement between the tracker and the scene, and control means for controlling the aim of the tracker in response to said correlation waveform to maintain the tracker aimed substantially at said scene, the improvement comprising zero crossing means in said circuit for converting Said analog electrical waveform to a digital electrical waveform, said memory storing said reference scene waveform as a digital waveform, said reference scene waveform and said current scene waveform being applied to said correlator as digital electrical waveforms.

Claim 25

In a correlation-type optical tracker comprising a field stop, means for focusing light energy from a selected field of view scene onto said stop, scanning means for effecting scanning of the scene, circuit means including light energy responsive means adapted to receive the light energy from said scanning means and to convert the same to an analog electrical waveform responsive to the spatial frequency content of said scene, memory means for storing a reference scene waveform, means for selectively entering a portion of said electrical waveform to provide a reference scene waveform, means for deriving said reference waveform from said memory means, correlator means for producing an output dependent on correlation of signals applied to it, means for applying said reference scene waveform and an electrical waveform corresponding to the current scene to said correlator means to produce a correlation waveform having modulations corresponding to the direction and magnitude of relative movement between the tracker and the scene, and control means for controlling the aim of the tracker in response to said correlation waveform to maintain the tracker aimed substantially at said scene, the improvement comprising zero crossing means in said circuit for converting Said analog electrical waveform to a digital electrical waveform, said memory storing said reference scene waveform as a digital waveform, said reference scene waveform and said current scene waveform being applied to said correlator as digital electrical waveforms.

Claim 26

The tracker according to claim 20, including other correlator means for producing an output dependent on correlation of signals applied to it, means for deriving a digital waveform from said memory means corresponding to said reference scene waveform, means for applying said reference scene digital waveform and a digital waveform corresponding to the current scene to said other correlator means to produce a control signal, and memory control means for controlling the entry of a waveform into said memory means in response to a predetermined value of said control signal.

Claim 27

The correlation tracker according to claim 20, wherein said scanning means includes rotatable reticle means having a predetermined pattern of light transmitting elements, said pattern of elements being repetitive and symmetrical about a geometric center, said center being offset with respect to the axis of rotation of said reticle to produce a circular nutation of said field of view.

Claim 28

In a motion sensing device for producing output signals responsive to the magnitude and direction of the relative movement between the sensing device and an object within the field of view scene comprising reticle means for repetitively scanning the scene, light energy sensitive means responsive to the radiant energy passing through said reticle means to produce an electrical signal corresponding to the light energy pattern of the current field of view scene, storage means for storing a reference signal corresponding to a reference scan of the field of view scene, and signal correlation means for producing an output dependent on local correlation of said current signal and said reference signal, the improvement comprising said reticle means comprising means for cyclically nutating the field of view, said means for nutating the field of view comprising a predetermined repetitive pattern of light transmitting elements, at least one repetition of the pattern of elements being offset in relation to another of said repetitions to introduce an effective nutation of the scene.

Claim 29

In a motion sensing device for producing output signals responsive to the magnitude and direction of the relative movement between the sensing device and an object within the field of view scene comprising reticle means for repetitively scanning the scene, light energy sensitive means responsive to the radiant energy passing through said reticle means to produce an electrical signal corresponding to the light energy pattern of the current field of view scene, storage means for storing a reference signal corresponding to a reference scan of the field of view scene, and signal correlation means for producing an output dependent on local correlation of said current signal and said reference signal, the improvement comprising said reticle means comprising means for cyclically nutating the field of view, said means for nutating the field of view comprising a predetermined repetitive pattern of light transmitting elements, at least one repetition of the pattern of elements being offset in relation to another of said repetitions to introduce an effective nutation of the scene.

Claim 30

The motion sensing device according to claim 23 wherein each repetition of said pattern of elements is arranged in a semirandom order to effect scanning of the scene in other than sequential linear order.

Claim 31

The motion sensing device according to claim 23 wherein said pattern of elements is symmetrical about a geometric center, said center being offset with respect to the axis of rotation of said reticle to produce an effective upright circular nutation of said field of view.

Claim 32

In a correlation-type optical tracker comprising a field stop, means for focusing light energy from a selected field of view scene onto said stop, means for effecting scanning of the scene, circuit means including light energy responsive means adapted to receive the light energy from the scanning means and to convert the same to an electrical waveform responsive to the spatial frequency content of the scene, memory means for storing a reference scene waveform, means for selectively entering a portion of the waveform into said memory means to provide a reference scene waveform, means for deriving said reference waveform from said memory means, correlator means for correlating said time delayed reference scene waveform and the waveform corresponding to the current scene to produce a correlation waveform, and means responsive to said correlation waveform including integrator means for controlling the aim of said tracker in response to said integrated signals to maintain said tracker aimed substantially at said scene, the improvement comprising other correlator means for correlating a reference scene waveform and a waveform corresponding to a current scene to produce a correlation signal, means for derivIng a waveform from said memory means corresponding to said reference scene waveform, means for applying said reference scene waveform and a waveform corresponding to the current scene to said other correlator means to produce a control signal, and memory control means for controlling the entry of a waveform into said memory means in response to a predetermined value of said control signal.

Claim 33

In a correlation-type optical tracker comprising a field stop, means for focusing light energy from a selected field of view scene onto said stop, means for effecting scanning of the scene, circuit means including light energy responsive means adapted to receive the light energy from the scanning means and to convert the same to an electrical waveform responsive to the spatial frequency content of the scene, memory means for storing a reference scene waveform, means for selectively entering a portion of the waveform into said memory means to provide a reference scene waveform, means for deriving said reference waveform from said memory means, correlator means for correlating said time delayed reference scene waveform and the waveform corresponding to the current scene to produce a correlation waveform, and means responsive to said correlation waveform including integrator means for controlling the aim of said tracker in response to said integrated signals to maintain said tracker aimed substantially at said scene, the improvement comprising other correlator means for correlating a reference scene waveform and a waveform corresponding to a current scene to produce a correlation signal, means for derivIng a waveform from said memory means corresponding to said reference scene waveform, means for applying said reference scene waveform and a waveform corresponding to the current scene to said other correlator means to produce a control signal, and memory control means for controlling the entry of a waveform into said memory means in response to a predetermined value of said control signal.