IMAGE GENERATION WITH INTERPOLATION AND DISTORTION CORRECTION

• US 20070291051A1
• Filed: 07/27/2007
• Published: 12/20/2007
• Est. Priority Date: 05/19/2003
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Champion, Mark, Freeman, Mark, Raghavan, Aarti, Brown, Margaret, Swilley, Shawn, Linden, Kelly
• Granted Patent: US 8,068,115 B2
• Time in Patent Office: Days
• US Class Current: 345/647
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen
• CPC Class Codes: G09G 3/025 with scanning or deflecting the beams in two directions or dimensions
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/022 using memory planes
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 3/08 having a moving reflector
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

An image generation apparatus provides interpolation and distortion correction. The interpolation and distortion correction may be provided in one or two dimensions. Nonlinear image scan trajectories, such as sinusoidal and bi-sinusoidal trajectories are accommodated. Horizontal and vertical scan positions are determined using a linear pixel clock, and displayed pixel intensities are determined using interpolation techniques.

Claims

1. An image generation apparatus comprising:

a frame buffer to hold a plurality of rows of pixel data corresponding to a grid of display pixels;

a row buffer coupled to the frame buffer to receive a current row of the plurality of rows of pixel data;

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory; and

an interpolation component coupled to receive pixel data from the row buffer and operable to interpolate between display pixels on either side of the horizontal scan position in the current row.

2. The image generation apparatus of claim 1 further comprising a vertical scan Is position determination component operable to approximate a vertical scan position of the scan trajectory as a different row for each horizontal sweep of the scan trajectory.

3. The image generation apparatus of claim 1 wherein the horizontal scan position determination component is operable to determine the horizontal scan position as a sine of an increasing angle plus a phase offset that is a function of color and vertical scan position.

4. The image generation apparatus of claim 1 wherein the horizontal scan position determination component is operable to determine the horizontal scan position as (a sine of an increasing angle) times a multiplier.

5. An image generation apparatus comprising:

a frame buffer to hold a plurality of rows of pixel data corresponding to a grid of display pixels;

a row buffer coupled to the frame buffer to receive more than one but fewer than all of the plurality of rows of pixel data;

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory; and

an interpolation component coupled to receive pixel data from the row buffer and operable to interpolate between display pixels on either side of the horizontal scan position.

6. The image generation apparatus of claim 5 further comprising a vertical scan position determination component to periodically determine a vertical scan position of the scan trajectory.

7. The image generation apparatus of claim 6 wherein the vertical scan position determination component is operable to determine the vertical scan position as a sum of sine functions.

8. The image generation apparatus of claim 6 wherein the horizontal and vertical scan position determination components include lookup tables to implement arbitrary scan trajectories.

9. The image generation apparatus of claim 8 wherein the vertical scan position determination component is operable to determine the vertical scan position as a linearly advancing position over time.

10. The image generation apparatus of claim 8 wherein the vertical scan position determination component is operable to determine the vertical scan position as a sine of an increasing angle.

11. The image generation apparatus of claim 8 wherein the row buffer is sized to hold a number of rows greater than or equal to the maximum possible number of rows traversed in a single horizontal sweep of the scan trajectory.

12. The image generation apparatus of claim 11 wherein the row buffer is operable to be loaded with a different set of rows of pixel data for each color to compensate for vertical misalignment of colors.

13. An image generation apparatus comprising:

a frame buffer to hold a plurality of rows of pixel data corresponding to a grid of display pixels;

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory as (the sine of an increasing angle) times a multiplier; and

an interpolation component coupled to receive pixel data from the frame buffer and operable to interpolate between display pixels on either side of the horizontal scan position.

14. The image generation apparatus of claim 13 wherein the multiplier is a function of a color.

15. The image generation apparatus of claim 13 wherein the multiplier is a function of a vertical scan position.

16. The image generation apparatus of claim 13 further comprising a vertical scan position determination component operable to approximate a vertical scan position of the scan trajectory as one row for each horizontal sweep of the scan trajectory.

17. The image generation apparatus of claim 16 wherein the interpolation component is operable to interpolate between pixel data in the one row.

18. The image generation apparatus of claim 16 wherein the interpolation component is further operable to interpolate between display pixels on either side of the vertical scan of the vertical scan position.

19. An image generation apparatus comprising:

a frame buffer to hold a plurality of rows of pixel data corresponding to a grid of display pixels;

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory as (the sine of an increasing angle) plus an offset; and

an interpolation component coupled to receive pixel data from the frame buffer and operable to interpolate between display pixels on either side of the horizontal scan position.

20. The image generation apparatus of claim 19 wherein the offset is a function of a color.

21. The image generation apparatus of claim 19 wherein the offset is a function of a vertical scan position.

22. The image generation apparatus of claim 19 further comprising a vertical scan position determination component operable to approximate a vertical scan position of the scan trajectory as one row for each horizontal sweep of the scan trajectory.

23. The image generation apparatus of claim 22 wherein the interpolation component is operable to interpolate between pixel data in the one row.

24. The image generation apparatus of claim 22 wherein the interpolation component is further operable to interpolate between display pixels on either side of the vertical scan of the vertical scan position.

25. An image generation apparatus comprising:

a first frame buffer to hold a plurality of rows and columns of pixel data;

a first interpolation mechanism coupled to receive pixel data from the first frame buffer and operable to interpolate between pixels within a row;

a buffer rotation mechanism to exchange columns and rows;

a second frame buffer to hold results from the buffer rotation mechanism; and

a second interpolation mechanism coupled to receive pixel data from the second frame buffer and operable to interpolate between pixels of the second frame buffer.

26. The image generation apparatus of claim 25 further comprising a horizontal scan position determination component operable to periodically determine a horizontal scan position of a scan trajectory as a sine of a linearly increasing angle.

27. The image generation apparatus of claim 26 wherein the first interpolation mechanism is operable to interpolate between pixel data on either side of the horizontal scan position.

28. The image generation apparatus of claim 25 wherein the first interpolation mechanism is operable to generate more pixel data per row than in the first frame buffer.

29. An image generation apparatus comprising:

an image warping and interpolation component having a number of rows and columns corresponding to a first resolution, the image warping and interpolation component operable to warp an image in response to a set of parameterized basis distortions;

a frame buffer to hold rows of pixel data resulting from the image warping and interpolation component;

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory;

a vertical scan position determination component to periodically determine a vertical scan position of the scan trajectory; and

an interpolation component coupled to receive pixel data from the frame buffer and operable to interpolate between display pixels on either side of the horizontal scan position and on either side of the vertical scan position to create an image with a resolution higher than the first resolution.

30. The image generation apparatus of claim 29 wherein the set of parameterized basis distortions are operable to pre-warp an image for display on a non-uniform surface.

31. The image generation apparatus of claim 29 wherein the set of parameterized basis distortions are operable to pre-warp an image for a head-up display.

32. A mobile device comprising:

a laser projector to project an image, the laser projector including an image generation apparatus having a frame buffer to hold a plurality of rows of pixel data corresponding to a grid of display pixels, a row buffer coupled to the frame buffer to receive more than one but fewer than all of the plurality of rows of pixel data, a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory, and an interpolation component coupled to receive pixel data from the row buffer and operable to interpolate between display pixels on either side of the horizontal scan position.

33. The mobile device of claim 32 further comprising a memory card slot.

34. The mobile device of claim 32 further comprising a communications receiver.

35. The mobile device of claim 32 further comprising a communications transceiver.

36. The mobile device of claim 35 wherein the communications transceiver is operable to communicate using cellular telephone signals.

37. A method comprising:

determining a horizontal scan position of a scan trajectory of an image generation apparatus as the sum of an offset and a scaled sine of an increasing angle;

horizontally interpolating between pixel data to the left and right of the horizontal scan position to determine a pixel intensity of a new pixel at the horizontal scan position; and

displaying the new pixel at the horizontal scan position.

38. The method of claim 37 further comprising:

determining a vertical scan position of the scan trajectory; and

vertically interpolating between pixel data above and below the vertical scan position; and

combining the horizontal and vertical interpolation to arrive at the pixel intensity of the new pixel at an intersection of the horizontal scan position and the vertical scan position.

39. The method of claim 37 wherein determining a horizontal scan position comprises scaling the sine with a multiplier that is a function of color.

40. The method of claim 37 wherein determining a horizontal scan position comprises scaling the sine with a multiplier that is a function of vertical scan position.