ELECTRONICALLY-GENERATED PERSPECTIVE IMAGES

• US 3,665,408 A
• Filed: 05/26/1970
• Issued: 05/23/1972
• Est. Priority Date: 05/26/1970
• Status: Expired due to Term

• Current Assignee: Alan C. Erdahl, David C. Evans
• Original Assignee: Alan C. Erdahl, David C. Evans
• Inventors: Erdahl, Alan C., Evans, David C.
• Primary Examiner(s): Henon, Paul J.
• Assistant Examiner(s): Chirlin, Sydney R.
• Application Number:
  US05/040,647
• Time in Patent Office: 728 Days
• Field of Search: 340/172.5,324A 315/18,22
• US Class Current: 345/634
• CPC Class Codes: G09G 1/06 using single beam tubes G09G1/26, G09G1/28 take precedence, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows G09G1/28 takes precedence; stereoscopic TV-systems, details thereof H04N13/00; oscilloscopes for three-dimensional representation G01R13/206; vectorscopes G01R13/208

Abstract

A method and system for generating point intensity control signals for producing complex images on an electronic display device. The image to be displayed is defined by data specifying bounded areas of the viewing screen of the display device together with an intensity function for that area. This data is fed in the order in which the bounded areas first appear in the scanning pattern of the display, utilized to generate point intensity control signals then updated for future use and stored in order. The appropriate data for each portion of the viewing screen is chosen from either the stored data or newly received data. A plurality of intensity functions may be specified by the data to provide images with constant linear and nonlinear intensities or any combinations thereof. In addition, provision is made for providing lines and overwriting the image.

Claims

1. A system for generating a pictorial image of an object on a display device from information about the surfaces of the object to be displayed, comprising:

input means for receiving data representative of surfaces of said objEct to be displayed;

display control means for generating intensity control signals responsive to the data transferred thereto;

a display device connected to said display control means to receive said intensity control signals;

storage means connected to said display control means for storing the data transferred to said display control means;

merge means connected to said input means and said storage means for selecting the data representative of the surface next to be displayed from either newly received data in said input means or previously received data in said storage means; and

circuit means connected between said merge means and said display control means for supplying the data selected by said merge means to said display control means.

2. The system of claim 1 wherein said data representative of surfaces comprises a plurality of boundary words with each of said boundary words defining both a boundary edge and an intensity function of the surface represented and wherein said input means includes buffer means for holding said boundary words and read-out means for supplying said boundary words to said merge means in the order received.

3. The system of claim 1 wherein said data defines the surfaces relative to the scanning pattern of said display device, and wherein said data is selected from either said input means or said storage means by said merge means in accordance with signals derived from said display control means and supplied to said merge means which represent the position of said scanning pattern for which intensity control signals are presently being generated.

4. The system of claim 3 wherein said merge means includes comparing means for comparing the data in said storage means with the data in said input means to determine the data next to be displayed on said display device according to the scanning pattern of the display device.

5. The system of claim 1 wherein said data is representative of the visible surfaces of the object to be displayed and wherein said data comprises a plurality of boundary words with each of said boundary words defining a single visible surface through specification of both a boundary edge and an intensity function of said surface in terms of the scanning pattern of the display device.

6. The system of claim 5 further having means responsive to each of said boundary words for controlling selected segments of said scanning pattern of the display device, and update processing means connected between said display control means and said storage means for updating each boundary word to be stored in said storage means for the next selected segment of said scanning pattern which said boundary word controls.

7. The system of claim 6 wherein said boundary words are stored in said storage means in the order in which said next selected segments appear in said scanning pattern of the display device.

8. The system of claim 6 wherein said update processing means includes test means for determining whether further selected segments of said scanning pattern are to be controlled by the boundary word being tested, said test means including means for storing said boundary word in said storage means only when further selected segments are to be controlled by that boundary word.

9. The system of claim 5 wherein said display control means comprises:

a register means connected to said circuit means for receiving the boundary words selected by said merge means, a plurality of intensity function control means for generating said intensity control signals responsive to the intensity function specified by the boundary word received by said register means, and gate means connected between said register means and said plurality of intensity control means for selectively controlling the transfer of the intensity function of the boundary word in said register means to one or more of said plurality of intensity control means, said gate means being selectively controlled by signals generated in reSponse to intensity instructions specified by the intensity function of the boundary word in said register means.

10. The system of claim 9 wherein said plurality of intensity function control means includes both a linear intensity means for generating an intensity control signal which varies linearly with respect to said scanning pattern and a constant intensity control means for generating an intensity control signal which is constant.

11. The system of claim 9 wherein said plurality of intensity control means includes overwrite means for generating intensity control signals which produce a constant intensity control signal for a predetermined portion of said scanning pattern of said display device regardless of newly received boundary words in said register means.

12. The system of claim 9 wherein said plurality of intensity control means includes non-linear intensity means for generating intensity control signals which vary non-linearly with respect to said scanning pattern.

13. The system of claim 12 wherein said non-linear intensity means comprises:

shift register means connected to said input means for receiving boundary words specifying a plurality of non-linear intensity values, and gate means connected between said shift register means and said display device for selectively supplying said non-linear intensity values to said display device in response to the intensity instructions of the boundary word in said register means.

14. The system of claim 5 wherein said boundary words are received by said input means in the order in which the visible surfaces defined by said boundary words first appear in the scanning pattern of the display.

15. The system of claim 1 further having means responsive to the data representative of the surfaces for controlling selected segments of said scanning pattern of the display device, and update processing means connected between said display control means and said storage means for updating said data to be stored in said storage means for the next selected segment of said scanning pattern which said data controls.

16. The system of claim 15 wherein the updated data is stored in said storage means in the order in which said next selected segments appear in said scanning pattern of the display device.

17. The system of claim 15 wherein said update processing means includes test means for determining whether further selected segments of said scanning pattern are to be controlled by said data being tested, and said test means includes means for storing said data in said storage means only when further selected segments are to be controlled by that data.

18. A method for displaying images on a display comprising:

providing data representative of bounded areas of the image to be displayed, said data being defined in terms of the scanning pattern of the display, selecting the data in the order in which segments of the bounded areas appear in the image to be displayed according to the scanning pattern of the display, generating intensity control signals in response to the selected data, and storing said data representative of each bounded area of the image to be displayed for reuse in generating intensity control signals after the data has been initially used and until intensity control signals have been generated for all of the segments in which that bounded area appears.

19. The method of claim 18 wherein the providing of data representative of the bounded areas of the image to be displayed include providing said data in the order in which said bounded areas appear in the image to be displayed according to the scanning pattern of the display, and wherein the selecting of the data is between previously stored data and newly provided data.

20. The method of claim 18 further comprising updating the data for each bounded area before storage thereof for the next segment of that bounded area to appear in the image to be displayed.

21. The method of claim 18 wherein the prOviding of data representative of bounded areas of the image to be displayed includes supplying signals representative of a boundary edge and an intensity function of each bounded area in terms of the scanning pattern of the display.

22. The method of claim 21 wherein the scanning pattern display is a raster scan.

23. The method of claim 22 wherein the boundary edge is defined in terms of the raster scan by specifying the scan lines on which the boundary edge appears and the position of the boundary edge along those scan lines.

24. The method of claim 23 wherein the scan lines in which the boundary edge appears and the position of the boundary edge along those scan lines are provided by specifying the initial scan line in which the boundary edge appears, the position of that boundary edge along that scan line, the total number of scan lines in which the boundary edge appears and the incremental change in the position of the boundary edge along each successive scan line in which the boundary edge appears.

25. The method of claim 24 further comprising updating the data for each bounded area before storage thereof for the next segment of that bounded area to appear in the image to be displayed.

26. The method of claim 25 wherein the data is updated before storage by adding the incremental change in the position of the boundary edge along the next scan line to the present value of the position along the current scan line and by subtracting the value one from the total number of scan lines in which that bounded area is to appear.

27. The method of claim 26 wherein the data representative of the total number of scan lines in which the boundary edge is to appear is tested before the data is updated to determine whether intensity control signals for all of the segments in which that boundary edge is to appear have been generated.

28. The method of claim 18 wherein the intensity control signals generated include a plurality of intensity functions with respect to the scanning pattern of the display dependent on the selected data.

29. The method of claim 18 wherein the intensity control signals generated vary linearly with respect to the scanning pattern of the display.

30. The method of claim 18 wherein the intensity signals generated vary non-linearly with respect to the scanning pattern of the display.

31. The method of claim 18 wherein the intensity control signals generated are constant with respect to the scanning pattern of the display.

32. The method of claim 18 further including selectively overwriting the intensity control signals generated in response to selected data by providing intensity control signals which produce constant intensity for a predetermined portion of said scanning pattern of the display.

33. The method of claim 18 wherein the scanning pattern of the display is a raster scan.

34. A system for generating an image on a display comprising:

input means for receiving data representative of bounded areas of the image to be displayed;

storage means for storing the data received;

selecting means connected to said input means and said storage means for selecting from either of said means the data representative of the bounded area next to be displayed;

display control means connected to said selecting means for generating from said selecting means control signals responsive to the data transferred thereto; and

display means connected to said display control means for receiving said control signals.

35. The system of claim 34 wherein said data is provided as a plurality of boundary words defining a boundary edge and an intensity function of the bounded area represented.

36. The system of claim 35 wherein said boundary words are transferred as a unit between the various means, and wherein the display control means includes a plurality of intensity function means for providing control signals in accordance with the intensity functions specified by each of said boundary words.

37. The system of claiM 36 wherein the scanning pattern of said display means is a raster scan, and wherein the boundary words define said boundary edges by specifying the initial scan line and the beginning position along that scan line at which said bounded area begins and the incremental change in said position along succeeding scan lines.

38. The system of claim 37 wherein the intensity function is defined by specifying an initial intensity at said position along said initial scan line and the incremental change in said intensity with respect to succeeding scan lines and along each scan line.

39. The system of claim 37 further including update processing means connected between said display control means and said storage means for updating each of said boundary words for the next scan line, said update processing means including a first adding means for adding said incremental change in position along each scan line to the beginning position along the previous scan line and a second adding means for adding the incremental change in intensity with respect to successive scan lines to the intensity at the beginning position of the previous scan line.

40. The system of claim 34 wherein said display control means includes an overwrite means for providing control signals which produce a constant intensity output over a predetermined area of said display means regardless of other data received.

41. The method of displaying shaded perspective images on a raster scan display device comprising:

supplying data representative of areas of the image to be displayed in the order in which they first appear in the scanning pattern of the display device, storing previously supplied data representative of areas of the image to be displayed until the scan of the display device is beyond the area represented, choosing the data representative of the next area to be displayed from said newly supplied data and said stored data, and controlling the intensity of the display device in accordance with the chosen data.

42. The method of claim 41 wherein the data representative of areas of the image comprises a plurality of data words, each said word controlling the intensity of the display device over an area of the display device defined by that word.

43. The method of claim 42 wherein each of said data words specifies an intensity function for controlling the intensity of the display device and the portion of the raster scan in which that intensity function is to control the intensity of the display device.

44. The method of claim 42 wherein each of said data words specifies the beginning point of the raster scan where that data word is to commence control of the intensity of the display device and wherein once that beginning point is reached by the display scan that data word controls the intensity of the display device until the beginning point of the next selected data word is reached.

45. The method of claim 42 wherein each data word controls the intensity of the display device by specifying an intensity function which may be either linear, constant or non-linear with respect to the raster scan of the display device.

46. The method of claim 45 wherein the linear intensity function is defined by specifying the initial intensity at the first point of the scan controlled by that data word and the incremental change in intensity along each scan line and for successive scan lines and wherein the said incremental changes are added to said initial intensity value as the scan of the display device progresses.

47. The method of claim 42 wherein the area of the display device in which each data word controls the intensity of the display device is defined by specifying the edge of said area first encountered by the scan in the raster scan pattern.

48. The method of claim 47 wherein the edge of the area first encountered is defined by specifying the first scan line and the position along that scan line where the edge appears, the incremental change in position along The scan for successive scan lines and the total number of scan lines in which the edge appears.

49. The method of claim 48 further comprising comprising:

updating each data word before storing by adding the incremental change in the position along the scan line to the position along the preceeding scan line, and by reducing the total number of scan lines in which the edge appears by one.

50. The method of claim 49 further comprising checking the total number of scan lines in which the edge appears of each data word after each updating and discarding said word when the total number equals zero.

51. The method of claim 42 wherein the data words are supplied in series in the order in which said data words first control said display device, wherein said data words are stored in the order in which they are utilized, and wherein the data word defining the next area to be displayed is chosen by comparing the earliest stored data word with the currently supplied data word to determine which of the areas of the display device controlled by those two data words occurs first in the raster scan.

52. A method for generating an image of a bounded area on a raster scan display comprising the steps of:

providing data representative of the bounded area to be displayed, the data being defined in terms of the raster pattern;

generating intensity control signals for a first raster line upon which the bounded area first appears in response to the selected data;

updating the data for a subsequent raster line of the display;

storing the updated data; and

generating intensity control signals for the subsequent raster line in response to the stored updated data.

53. The method of claim 52 wherein the data defines boundary edges of the bounded area by specifying the initial scan line (Yo) in which each boundary edge appears, the last scan line (Yc) in which each boundary edge appears, the initial position along the initial scan line at which the boundary edge appears (Xo), and the incremental change in position of each boundary edge along each scan line with respect to a change from one scan line to the next ( Delta X/ Delta Y).

54. The method of claim 53 wherein the data is updated between the initial and last scan line by adding the incremental change in position of the boundary edge to the initial position of the boundary edge for each scan line subsequent to the initial scan line.