DICTORIAL TRACKING AND RECOGNITION SYSTEM WHICH PROVIDES DISPLAY OF TARGET IDENTIFIED BY BRILLIANCE AND SPATIAL CHARACTERISTICS

• US 3,562,423 A
• Filed: 08/15/1967
• Issued: 02/09/1971
• Est. Priority Date: 08/15/1967
• Status: Expired due to Term

• Current Assignee: Gordon J. Murphy
• Original Assignee: Gordon J. Murphy
• Inventors: Murphy, Gordon J.
• Application Number:
  US04/660,835
• Time in Patent Office: 1,274 Days
• US Class Current: 348/170
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems

Abstract

Target selector and video level detector means, operable by an attendant, select a target displayed on a monitor by spatial and brightness characteristics. Processor means analyze the selected target characteristics to obtain error signals indicative of the displacement of the target from the central region of the monitor field of view, and servomeans controlled by the error signals lock the camera to the target to effect centered display of the target on the monitor.

Claims

1. In a pictorial tracking and recognition system having display means, electronic sensor means for providing information signals representative of detected information in a field for presentation on said display means, target selector means connected to said electronic sensor means for providing signals which define a target area in said field, video level detector means including brightness selector means for selecting a brightness range for a significant target within said target area having minimum and maximum values, and brightness detector means connected to said target selector means and said brightness selector means to gate to said display means only those information signals which have a brightness in the range selected by said brightness selector means and which occur in said target area selected by said target selector means.

2. A system as set forth in claim 1 in which said brightness detector means in said video level detector means includes output means for providing a quantized signal output to said display means which represents said target.

3. A system as set forth in claim 1 in which said brightness detector means includes gate means for extending information signals generated by said sensor means to said display means, and comparator means connected to said target selector means and said brightness selector means for enabling said gate means only when a significant target represented by signals within said selected range is detected.

4. A system as set forth in claim 3 which includes means connected to said target selector means for extending only information signals from said sensor means to said brightness detector means which are within said target area.

5. A system as set forth in claim 1 in which said brightness selector means in said video level detector includes a first means for selecting a maximum signal level for the selected target, and a second means for selecting a minimum signal level for the selected target, and in which said brightness detector means includes comparator means connected to said target selector means and said first and second means for providing an output signal only when the level of said information signals provided by said sensor means is within the range of levels selected by said first and second means.

6. A system as set forth in claim 1 in which said target selector means includes means for gating to said video level detector means only the ones of said information signals which represent information in said target area.

7. A system as set forth in claim 1 which includes marker means in said target selector means for providing signals to said display means which outline the selected target area on said display means.

8. A system as set forth in claim 1 in which said target selector means includes marker means for providing signals which outline a selected target area on said display means, and which includes target marker adapter means having input means connected to the output of said video level detector means, and output means connected to control said marker means to provide signals which outline the selected significant target on said display means.

9. A system as set forth in claim 1 which includes tracking computer means connected to said sensor means to continually adjust the field of said sensor means to maintain the target selected by said target selector means in the field of said sensor means.

10. A system as set forth in claim 1 in which said target selector means has target-gaTing means for controlling gating of said target area signals to said video level detector means, and which includes target marker adapter means comprising input means connected to the signal output of said brightness detector means, comparator means for comparing said signal output with a reference signal to determine the presence of a target of a selected brightness feature, means controlled by said comparator means whenever a target is detected to control transmission of said signals to said target-gating means, and means controlled by said comparator means in the absence of said target to control transmission of an enabling signal to said target-gating means.

11. In a pictorial tracking and recognition system having display means including means for generating a raster on said display means, sensor means for providing information signals representative of detected information in a field for presentation on said display means, target selector means connected to said sensor means for providing signals which define a target area in said field comprising first reference means for selecting the X coordinates of said target area on said display means including a first selector means for selecting the first X coordinate of each line in the target area, and a second selector means for selecting the last X coordinate of each line in the target area, and first generator means connected to said first and second selector means for providing an X coordinate signal output in each raster line only during the period of raster line trace between the selected X coordinates, a second reference means for selecting the vertical coordinates of said target area including a third selector means for selecting the Y coordinate for the first raster line of the target area and a fourth selector means for selecting the Y coordinate for the last raster line of the target area, and second generator means connected to said third and fourth selector means for providing a Y coordinate signal output only during the period of trace of the raster lines between the lines having the selected Y coordinates, and target gating means connected to said first and second generator means for providing signals to said display means only during the time period in said raster trace of concurrent signal output from said first and second generator means.

12. A system as set forth in claim 11 in which said target-gating means includes differentiating means for differentiating the leading and trailing edge of the signals from said first and second generator means.

13. A system as set forth in claim 11 which includes means connected to the output of said first and second generator means including target marker adapter means operative to provide signals to the input for said target-gating means to control same to provide a display of the outline of the target.

14. A system as set forth in claim 11 which includes a video level detector connected to the output of said target-gating means for detecting significant targets in a predetermined brightness range in said target area, and means in said target-gating means for transmitting information signals from said sensor means to said video level detector means only during the period of concurrent signal output of said first and second generator means.

15. A system as set forth in claim 11 in which said first selector means comprise voltage means for providing an upper level voltage and said second selector means comprises voltage means for providing a lower level voltage for selecting the horizontal coordinates of the target area, and said first generator means includes means connected to the output of said first and second selector means for computing the average value of said upper level and lower level voltages, a first means for subtracting said average value voltage from said upper level voltage to provide a modified upper level voltage, and a second means for subtracting said average value from said lower level voltage to providE a modified lower level voltage, comparator means for comparing the modified lower level voltage with the modified upper level voltage, mixer means, and a first and second transmission gate controlled by the output of comparator means to selectively gate the modified lower or upper level voltage to said mixer means, a first comparator means for comparing the output of said mixer means with the horizontal scan signals for said display means, and a second comparator means for comparing the output of said second means with said horizontal scan signals, and means controlled by said comparator means to provide a gating signal output for the period of raster trace of the X coordinates selected by said first reference means.

16. In a pictorial tracking and recognition system having display means, electronic sensor means for providing signals representative of information detected in a given field, target selector means connected to said electronic sensor means for providing signals defining a selected target area in said field, video level detector means connected to said target selector means for selecting a significant target of an established brightness within said target area having a minimum and a maximum brightness value including means for providing output signals in response to detection of said significant target in said field, tracking means including actuator means connected to said sensor means for continually positioning said sensor means to maintain said target in its field of sensing, and means connected to said video level detector for connecting signals to said tracking means for use in controlling the operation of said actuators and positioning of said sensor means.

17. A system as set forth in claim 16 in which said tracking means includes means for detecting the X, Y distances of a reference point for said selected target from a predetermined reference point on the display means, and means for providing error signals related to said distances to said actuator means.

18. A system as set forth in claim 16 in which said tracking means includes means for providing signals indicating the total area of the selected target, first means for computing the first moment of the selected target about a vertical axis through the center of the display, means for dividing said first moment by said total area to obtain a signal indicating the mean value of horizontal displacement of the selected target from the display center, means for computing the first vertical moment of the selected target about a horizontal axis through the display center, and means for dividing said first moment by the total area of the selected target to obtain the mean value of the vertical displacement of the selected target from the display center, and means for coupling the resultant signals to said actuator means.

19. A system as set forth in claim 18 in which said last means includes sample and hold circuits for providing an output to said actuator means between successive sampling instants which are equal to its input at the most recent sampling instant.

20. A system as set forth in claim 16 which includes switch means for enabling the operator to disable said tracking means, and to effect scanning movement of the sensor means independent of the output of said tracking means.

21. A system as set forth in claim 16 in which said actuator means comprises a first actuator for altering the azimuth alignment of said sensor means at a rate approximately proportional to the mean value of the calculated horizontal displacement, and a second actuator for altering the elevational alignment of said sensor means at a rate approximately proportional to the mean value of the calculated vertical displacement.

22. In a pictorial tracking and recognition system having display means, electronic sensor means for providing information signals representative of detected targets in a field for presentation on said display means, first means including selector means for establishing predeTermined identifiable characteristics for a target in said field, second means for selectively gating information signals from said sensor means to said first means, third means in said first means connected to said selector means and said second means operative to provide output signals to said display means only in response to receipt of information signals provided by said sensor means which have the predetermined identifiable characteristics selected by said selector means, and fourth means including target marker adapter means connected to the output of said third means operative to provide signals which trace the contour of the target on said display means.

23. A system as set forth in claim 22 in which said first means includes brightness selector means for establishing a predetermined brightness for the selected target, and in which said third means includes comparator means connected to said selector means and said second means for providing output signals to said display means only when the information signals for a target are of said predetermined brightness.

24. A system as set forth in claim 23 in which said third means includes output means for providing a quantized signal to said target marker adapter means, and in which said fourth means include means for modifying said quantized signals to provide display of the target contour on said display means.

25. In a pictorial tracking and recognition system having display means, electronic sensor means for providing information signals representative of detected information in a field for presentation on said display means, target selector means connected to said electronic sensor means for providing signals which display a target area in said field, video level detector means including brightness selector means for selecting a predetermined brightness for a significant target within said target area, and brightness detector means connected to said target selector means said brightness selector means to gate to said display means only those information signals provided by said sensor means which are in the target field selected by said target selector means and which have a brightness selected by said selector means, and target adapter means responsive to the output signals of said brightness detector means for controlling said target selector means to provide a display of the contour of said target on said display means in lieu of said target area display.