Double stacked projection

• US 8,842,222 B2
• Filed: 04/18/2011
• Issued: 09/23/2014
• Est. Priority Date: 04/18/2010
• Status: Active Grant

• Current Assignee: IMAX Corporation
• Original Assignee: IMAX Corporation
• Inventors: Iversen, Steen Svendstorp
• Primary Examiner(s): Harold, Jefferey
• Assistant Examiner(s): HAIEM, SEAN N
• Application Number:
  US13/641,676
• Publication Number:
  US 20130201403A1
• Time in Patent Office: 1,254 Days
• Field of Search: None
• US Class Current: 348/659
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 3/18 Image warping, e.g. rearranging pixels individually
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: H04N 13/106 Processing image signals for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/327 Calibration thereof
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 13/39 the picture elements emitting light at places where a pair of light beams intersect in a transparent material
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/67 for matrixing camera processing pipelines for matrixing of colour signals H04N23/85

Abstract

A method for producing a first output image and a second output image for being projected by a first projector and a second projector, respectively, is disclosed. The method comprises: providing a source image comprising a plurality of pixels, each pixel having a source value, providing an inverted threshold value for each pixel of the plurality of pixels, and generating thereof a temporary image comprising a temporary value for each pixel of the plurality of pixels. The method further comprises: generating the first output image comprising a first output value for each pixel of the plurality of pixels, the first output value being generated from the temporary value and the source value for each pixel, and generating the second output image comprising a second output value for each pixel of the plurality of pixels, the second output value being generated from the temporary value.

Claims

1. A method of producing from a received image and a threshold image a first image and a second image, comprising:

determining an upper bound image and a lower bound image based on pixel values of each of the received image and the threshold image;

producing the first image and the second image by using a smoothing filter process in combination with the upper bound image, the lower bound image, the received image and the threshold image, wherein the first image has a different spatial content frequency than the second image based on the smoothing filter process;

projecting the first image onto a surface by a first projector; and

projecting the second image onto the surface by a second projector,

wherein the first image and the second image have pixel values that are within illumination limits of the first projector and the second projector.

2. The method of claim 1, wherein the lower bound image represents pixel values that exceed a illumination intensity limit of the first projector or the second projector.

3. The method of claim 1, wherein the upper bound image represents maximum pixel values contributable by the first projector or the second projector onto the surface.

4. The method of claim 1, wherein determining the lower bound image comprises:

i. determining for each corresponding pixel between the received image and the threshold image a maximum pixel value; and

ii. determining a difference value by subtracting a corresponding threshold value from the maximum pixel value for each pixel,

wherein determining the upper bound image comprises determining for each corresponding pixel between the received image and an inverted threshold image the minimum pixel value.

5. The method of claim 1, further comprising:

balancing illumination between the first projector and the second projector by controlling a representation of a fraction of illumination intensity in the threshold image for each pixel of which the first projector and the second projector contributes to the surface.

6. The method of claim 1, wherein the smoothing filter process comprises:

i. receiving the upper bound image and the lower bound image; and

ii. performing a dilation operation followed by a blur operation on each pixel of the lower bound image.

7. The method of claim 6, wherein the smoothing filter process further comprises determining a minimum of corresponding pixels of a filtered lower bound image and the upper bound image for each pixel.

8. The method of claim 1, further comprising:

gamma decoding the received image.

9. The method of claim 1, further comprising:

gamma encoding the first image prior to projecting the first image; and

gamma encoding the second image prior to projecting the second image.

10. The method of claim 1, further comprising:

warping at least one of the first image or the second image prior to projecting the first image and projecting the second image.

11. The method of claim 1, further comprising:

balancing intensity of the first image and the second image,

wherein the smoothing filter process comprises a constrained smoothing filter process.

12. The method of claim 1, wherein projecting the second image onto the surface by the second projector comprises:

causing the second image to be superimposed and geometrically aligned with the first image projected by the first projector.

13. The method of claim 1, wherein producing the first image comprises:

determining a difference of corresponding pixels between the received image and an image outputted from the smoothing filter process; and

dividing by corresponding pixels of the threshold image for each pixel.

14. The method of claim 13, wherein producing the second image comprises dividing an output of the smoothing filter process with corresponding pixels of an inverted threshold image for each pixel.

19. The method of claim 1, further comprising:

limiting a projector illumination intensity demand to within an illumination intensity contribution capability of each of the first projector and the second projector using the threshold image.

20. The method of claim 19, wherein the threshold image is a fraction of a total illumination intensity that is contributed by the first projector or the second projector, the total illumination intensity being an illumination on the surface of a corresponding pixel value of the first image and the second image projected on the surface, the fraction representing the illumination intensity that one of the first projector or the second projector is able to contribute to the corresponding pixel value.

21. The method of claim 20, wherein the threshold image is a spatial distribution of the fraction of the total illumination intensity that is contributed by the first projector or the second projector.

22. The method of claim 1, wherein the first image projected onto the surface and the second image projected onto the surface are misaligned by a misalignment amount to produce a visible misalignment artefact that is less visible than the first projector and the second projector projecting the received image with a misalignment of the misalignment amount.

15. An image projection system, comprising:

image processing circuitry configured for;

generating a first image and a second image from an input image using a constrained smoothing filter process, wherein the first image and second image are different based on the constrained smoothing filter process;

balancing intensity of the first image and the second image; and

producing a warped image by warping the second image;

a first projector for projecting the first image;

a second projector for projecting the warped image; and

a screen on which the first image projected by the first projector is configured to be superimposed and geometrically aligned with the warped image projected by the second projector.

16. The image projection system of claim 15, wherein the image processing circuitry is configured for:

determining an upper bound image and a lower bound image based on pixel values of each of the input image and a threshold image;

generating the first image and the second image by using the constrained smoothing filter process in combination with the upper bound image and the lower bound image; and

causing the first image and the warped image to have pixel values that are within illumination limits of the first projector and the second projector.

17. An image projection system, comprising:

a first projector for projecting a first image;

a second projector for projecting a second image having different spatial content frequency than the first image to overlay the first image on a projection surface; and

image processing circuitry adapted for generating the first image and the second image from a received image using at least one smoothing filter in combination with an upper bound image and a lower bound image determined based on pixel values of each of the received image and a threshold image.

18. The image projection system of claim 17, wherein the image processing circuitry is adapted for:

generating the first image and the second image having pixel values that are within illumination limits of the first projector and the second projector; and

generating the second image having different spatial content frequency than the first image based on the at least one smoothing filter.