Computer generated image simulator

• US 4,303,394 A
• Filed: 07/10/1980
• Issued: 12/01/1981
• Est. Priority Date: 07/10/1980
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Allen, John H., Berke, Herbert, Owen, Joseph R.
• Primary Examiner(s): Hum, Vance Y.
• Application Number:
  US06/167,276
• Time in Patent Office: 509 Days
• Field of Search: 434/38, 434/40, 434/43, 434/44, 434/20, 434/25, 434/26, 434/69, 434/36, 434/35, 434/34, 358/104
• US Class Current: 434/40
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G09B 9/302 the image being transformed by computer processing, e.g. updating the image to correspond to the changing point of view
• CPC Class Codes: G09B 9/307 by helmet-mounted projector or display G09B9/36 takes precedence; optical parts of head-up displays G02B27/01

Abstract

A computer generated image simulator is disclosed for scanning a visual target and then providing a visual image of the target which is to be displayed upon a reflective display screen such that a trainee pilot may observe the target. A head tracker which monitors the position of the trainee pilot'"'"'s head, and an eye tracker which monitors the position of the trainee pilot'"'"'s eyes, respectively provide head and eye orientation signals to be processed by electronic circuitry such that the target which is projected upon the reflective display screen by a helmet mounted projector will be orientated upon the screen in accordance with the orientation of the trainee pilot'"'"'s head.

Claims

1. A computer generated image simulator comprising, in combination:

a helmet adapted to be worn upon the head of a trainee pilot;

head tracking means connected to said helmet for continuously monitoring the horizontal, vertical, and rotational movement of the head of said trainee pilot, and for providing at the output thereof horizontal, vertical, and rotational head orientation signals indicative of such movement, said head tracking means having first, second, and third outputs;

eye tracking means connected to said helmet in such a manner so as to be in alignment with the line of sight of said trainee pilot for continuously monitoring the horizontal and vertical movement of the eyes of said trainee pilot, and for providing at the output thereof horizontal and vertical eye orientation signals indicative of such movement, said eye tracking means having first and second outputs;

timing circuit means having an input connected to the first output of said head tracking means for delaying said rotational head orientation signal for a first predetermined time interval;

a visual target;

servomechanism means effectively connected between the output of said timing circuit means and said visual target for effecting the rotational movement of said visual target in accordance with said delayed rotational head orientation signal;

first summing circuit means having a first input connected to the second output of said head tracking means, a second input connected to the first output of said eye tracking means and an output for delaying said horizontal head and eye orientation signals for a second predetermined time interval and for combining said delayed horizontal head and eye orientation signals so as to form a horizontal movement indicator signal;

second summing circuit means having a first input connected to the third output of said head tracking means, a second input connected to the second output of said eye tracking means and an output for delaying said vertical head and eye orientation signals for a third predetermined time interval, and for combining said delayed vertical head and eye orientation signals so as to form a vertical movement indicator signal;

first camera means positioned in front of said visual target and having an input and an output for continuously scanning said visual target and the rotational movement associated therewith, and for providing a first video signal in response to the scanning of said visual target thereby;

control means having a first control output connected to the input of said first camera means, a second control output, a first sync output, and a second sync output for generating a first control signal so as to effect the scanning of said visual target by said first camera means, a second control signal, a first sync signal, and a second sync signal;

horizontal ramp generating means having a sync input connected to the first sync output of said control means, a data input connected to the output of said first summing circuit means, and an output for producing a first sawtooth waveform signal in response to said first sync signal, and for combining said first sawtooth waveform signal with said horizontal movement indicator signal so as to provide at the output thereof a first raster drive signal;

vertical ramp generating means having a sync input connected to the second sync output of said control means, a data input connected to the output of said second summing circuit means and an output for producing a second sawtooth waveform signal in response to said second sync signal and for combining said second sawtooth waveform signal with said vertical movement indicator signal so as to provide at the output thereof a second raster drive signal;

image display means having a television screen therein, and a trio of data inputs with the trio of data inputs thereof respectively connected to the output of said first camera means, the output of said horizontal ramp generating means, and the output of said vertical ramp generating means for reproducing upon said television screen said visual target and the rotational movement associated therewith in response to said first video signal, and for varying the position of said visual target upon said television screen in accordance with the movement of the head and eyes of said trainee pilot in response to said first and second raster drive signals;

second camera means positioned in front of the television screen of said image display means and having an input connected to the output of said control means, and an output for scanning the visual target reproduced upon the television screen of said image display means, and for providing a second video signal in response to the scanning of said visual target thereby;

a reflective display screen substantially encompassing the field of view of said trainee pilot; and

means mounted upon said helmet and having an input effectively connected to the output of said second camera means for projecting upon said reflective display screen said visual target in response to said second video signal.

2. The computer generated image simulator of claim 1, wherein said servomechanism means comprises:

a servomechanism circuit having an input connected to the output of said timing circuit means; and

a drive motor having an input connected to the output of said servomechanism circuit.

3. The computer generated image simulator of claim 1, wherein said visual target comprises an aircraft.

4. The computer generated image simulator of claim 1, wherein said timing circuit means comprises:

a variable gain amplifier having an input connected to the first output of said head tracking means, and an output;

a first level shifting amplifier having an output connected to the output of said variable gain amplifier, and an output;

an adjustable frequency clock signal generator having an output;

a trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

an analog shift register having a first clock input connected to the Q output of said trigger flip-flop, a second clock input connected to the Q output of said trigger flip-flop, a data input connected to the output of said first level shifting amplifier, and an output;

a filter network having an input connected to the output of said analog shift register, and an output;

a second level shifting amplifier having an input connected to the output of said filter network, and an output;

a first selector switch having a first input connected to the output of said first variable gain amplifier, a second input connected to the output of said second level shifting amplifier, and an output;

an inverting amplifier having an input connected to the output of said first selector switch, and an output;

a second selector switch having a first input connected to the output of said inverting amplifier, a second input connected to the output of said first selector switch, and an output;

a summing amplifier having an input connected to the output of said second selector switch, and an output; and

a buffer amplifier having an input connected to the output of said summing amplifier.

5. The computer generated image simulator of claim 1, wherein each of said summing circuit means comprises:

a first input terminal;

a first variable gain amplifier having an input connected to said first input terminal, and an output;

a second input terminal;

a second variable gain amplifier having an input connected to said second input terminal, and an output;

a first level shifting amplifier having an input connected to the output of said first variable gain amplifier, and an output;

a second level shifting amplifier having an input connected to the output of said second variable gain amplifier, and an output;

an adjustable frequency clock signal generator having an output;

a first trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

a first analog shift register having a first clock input connected to the Q output of said first trigger flip-flop, a second clock input connected to the Q output of said first trigger flip-flop, a data input connected to the output of said first level shifting amplifier, and an output;

a second trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

a second analog shift register having a first clock input connected to the Q output of said second trigger flip-flop, a second clock input connected to the Q output of said second trigger flip-flop, a data input connected to the output of said second level shifting amplifier, and an output;

a first filter network having an input connected to the output of said first analog shift register, and an output;

a second filter network having an input connected to the output of said second analog shift register, and an output;

a third level shifting amplifier having an input connected to the output of said first filter network, and an output;

a fourth level shifting amplifier having an input connected to the output of said second filter network, and an output;

a first selector switch having a first input connected to the output of said first variable gain amplifier, a second input connected to the output of said third level shifting amplifier, and an output;

a second selector switch having a first input connected to the output of said second variable gain amplifier, a second input connected to the output of said fourth level shifting amplifier, and an output;

a first inverting amplifier having an input connected to the output of said first selector switch, and an output;

a second inverting amplifier having an input connected to the output of said second selector switch, and an output;

a third selector switch having a first input connected to the output of said first inverting amplifier, a second input connected to the output of said first selector switch, and an output;

a fourth selector switch having a first input connected to the output of said second inverting amplifier, a second input connected to the output of said second selector switch, and an output;

a summing amplifier having an input effectively connected to the output of said third and fourth selector switches, and an output; and

a buffer amplifier having an input connected to the output of said variable gain amplifier.

6. The computer generated image simulator of claim 1, further characterized by:

a computer having a first input connected to the output of said timing circuit means, a second input connected to the output of said first summing circuit means, and a third input connected to the output of said second summing circuit means;

a computer image generator having an input connected to the output of said computer; and

a selector switch having a first input connected to the output of said computer image generator, a second input connected to the output of said second camera means, and an output connected to the input of said projecting means.

7. A head trackable wide angle visual display system simulator comprising, in combination:

a helmet adapted to be worn upon the head of a trainee pilot;

a head tracker connected to said helmet, said head tracker having first, second, and third data outputs;

an eye tracker connected to said helmet in such a manner so as to be in alignment with the line of sight of said trainee pilot, said eye tracker having first and second data outputs;

a roll buffer circuit having a data input connected to the first data output of said head tracker, a delay input, a first data output, and a second data output;

a roll delay circuit having an input connected to the first data output of said roll buffer circuit and an output connected to the delay input of said roll buffer circuit;

a horizontal summing circuit having a first data input connected to the second data output of said head tracker, a second data input connected to the first data output of said eye tracker, first and second delay inputs, and first, second, and third data outputs;

a horizontal delay circuit having first and second inputs respectively connected to the first and second data outputs of said horizontal summing circuit, and first and second outputs respectively connected to the first and second delay inputs of said horizontal summing circuit;

a vertical summing circuit having a first data input connected to the third data output of said head tracker, a second data input connected to the second data output of said eye tracker, first and second delay inputs, and first, second, and third data outputs;

a vertical delay circuit having first and second inputs respectively connected to the first and second data outputs of said vertical summing circuit, and first and second outputs respectively connected to the first and second delay inputs of said vertical summing circuit;

a camera controller having a first sync output, a second sync output, a first control output, and a second control output;

a horizontal ramp generator having a data input connected to the third data output of said horizontal summing circuit, a sync input connected to the first sync output of said camera controller, and an output;

a vertical ramp generator having a data input connected to the third data output of said vertical summing circuit, a sync input connected to the second sync output of said camera controller, and an output;

a servomechanism having an input connected to the second data output of said roll buffer circuit, and an output;

a drive motor having a drive shaft, and an input connected to the output of said servomechanism;

a visual target affixed to the shaft of said drive motor;

a first television camera positioned in front of said visual target, said first television camera having an input connected to the first control output of said camera controller, and an output;

a display apparatus having a television screen therein, and a trio of data inputs with the trio of data inputs thereof respectively connected to the output of said first television camera, the output of said horizontal ramp generator, and the output of said vertical ramp generator;

a second television camera positioned in front of the television screen of said display apparatus, said second television camera having an input connected to the second control output of said camera controller, and an output;

a selector switch having a first input connected to the output of said second television camera, a second input, and an output; and

a projector mounted upon said helmet, said projector having an input connected to the output of said selector switch.

8. The head trackable wide angle visual display system simulator of claim 7, wherein said roll buffer circuit comprises:

a variable gain amplifier having an input connected to the first data output of said head tracker, and an output connected to the input of said roll delay circuit;

a first selector switch having a first input connected to the output of said variable gain amplifier, a second input connected to the output of said roll delay circuit; and

an output;

an inverting amplifier having an input connected to the output of said first selector switch, and an output;

a second selector switch having a first input connected to the output of said inverting amplifier, a second input connected to the output of said first selector switch, and an output;

a summing amplifier having an input connected to the output of said second selector switch, and an output; and

a buffer amplifier having an input connected to the output of said summing amplifier.

9. The head trackable wide angle visual display system simulator of claim 7, wherein said roll delay circuit comprises:

an adjustable frequency clock signal generator having an output;

a trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

a first level shifting amplifier having an input connected to the first data output of said roll buffer circuit, and an output;

an analog shift register having a first clock input connected to the Q output of said trigger flip-flop, a second clock input connected to the Q output of said trigger flip-flop, a data input connected to the output of said first level shifting amplifier, and an output;

a filter network having an input connected to the output of said analog shift register, and an output; and

a second level shifting amplifier having an input connected to the output of said filter network.

10. The head trackable wide angle visual display simulator of claim 7, wherein said horizontal and vertical summing circuits each comprise:

a first input terminal;

a variable gain amplifier having an input connected to said first input terminal, and an output;

a second input terminal;

a first selector switch having a first input connected to the output of said first variable gain amplifier, a second input connected to said second input terminal, and an output;

a first inverting amplifier having an input connected to the output of said first selector switch, and an output;

a second selector switch having a first input connected to the output of said first inverting amplifier, a second input connected to the output of said first selector switch, and an output;

a third input terminal;

a second variable gain amplifier having an input connected to said third input terminal, and an output;

a fourth input terminal;

a third selector switch having a first input connected to the output of said second selector switch, a second input connected to said fourth input terminal, and an output;

a second inverting amplifier having an input connected to the output of said third selector switch, and an output;

a fourth selector switch having a first input connected to the output of said second inverting amplifier, a second input connected to the output of said third selector switch, and an output;

a summing amplifier having an input effectively connected to the output of said second and fourth selector switches, and an output; and

a buffer amplifier having an input connected to the output of said summing amplifier.

11. The head trackable wide angle visual display system simulator of claim 7, wherein said horizontal and vertical display lines each comprise:

an adjustable frequency clock signal generator having an output;

a first trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

a first input terminal;

a first level shifting amplifier having an input connected to said first input terminal;

a first analog shift register having a first clock input connected to the Q output of said trigger flip-flop, a second clock input connected to the Q output of said trigger flip-flop, a data input connected to the output of said first level shifting amplifier, and an output;

a first filter network having an input connected to the output of said first analog shift register, and an output;

a second level shifting amplifier having an input connected to the output of said first filter network;

a second trigger flip-flop having a clock input connected to the output of said adjustable frequency clock signal generator, a Q output, and a Q output;

a second input terminal;

a third level shifting amplifier having an input connected to said second input terminal, and an output;

a second analog shift register having a first clock input connected to the Q output of said second trigger flip-flop, a second clock input connected to the Q output of said second trigger flip-flop, a data input connected to the output of said third level shifting amplifier, and an output;

a second filter network having an input connected to the output of said second analog shift register, and an output; and

a fourth level shifting amplifier having an input connected to the output of said second filter network.

12. The head trackable wide angle visual display system simulator of claim 7, wherein said visual target comprises an aircraft.

13. The head trackable wide angle visual display system simulator of claim 7, further characterized by a reflective display screen spatially disposed downstream from the projector mounted upon said helmet.

14. The head trackable wide angle visual display system simulator of claim 7, further characterized by:

a computer having a first input connected to the output of said roll buffer circuit, a second input connected to the output of said horizontal summing circuit, a third input connected to the output of said vertical summing circuit, and an output; and

a computer image generator having an input connected to the output of said computer, and an output connected to the second input of said selector switch.