Method and display for showing a stereoscopic image

• US 9,414,049 B2
• Filed: 09/09/2012
• Issued: 08/09/2016
• Est. Priority Date: 09/19/2011
• Status: Active Grant

• Current Assignee: Looking Glass Factory, Inc.
• Original Assignee: Crans Polaires Incorporated / Polar Screens Incorporated
• Inventors: Gaudreau, Jean-Etienne
• Primary Examiner(s): Senfi, Behrooz
• Application Number:
  US14/345,511
• Publication Number:
  US 20140320614A1
• Time in Patent Office: 1,430 Days
• Field of Search: 348/51
• US Class Current: 1/1
• CPC Class Codes: G02B 30/27 involving lenticular arrays
• CPC Class Codes: H04N 13/106 Processing image signals for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/302 for viewing without the aid of special glasses, i.e. using autostereoscopic displays
• CPC Class Codes: H04N 13/31 using parallax barriers
• CPC Class Codes: H04N 13/315 the parallax barriers being time-variant
• CPC Class Codes: H04N 13/366 using viewer tracking
• CPC Class Codes: H04N 13/371 for tracking viewers with different interocular distances; for tracking rotational head movements around the vertical axis
• CPC Class Codes: H04N 13/376 for tracking left-right translational head movements, i.e. lateral movements
• CPC Class Codes: H04N 2013/0074 Stereoscopic image analysis

Abstract

A method of generating stereoscopic images and an autostereoscopic system are introduced. Stereoscopic images are obtained by generating, on a screen, a first image having a pattern comprising alternating columns of N left-image pixels or sub-pixels and of N right-image pixels or sub-pixels and a second image having a reversed pattern from the pattern of the first image. A parallel-strip barrier has alternating strips for blocking alternating columns of the first and second images. A tracking system provides position information related to a viewer of the stereoscopic image. A controller shifts to the left or to the right, in relation to the strips of the barrier, the image columns by a number of image pixels or sub-pixels as a function of the position of the viewer.

Claims

1. A method for displaying a stereoscopic image, comprising:

generating a first image having a pattern comprising alternating columns of N left-image pixels or sub-pixels and of N right-image pixels or sub-pixels;

generating a second image having a reversed pattern from the pattern of the first image;

blocking alternating columns of the first and second images in alternating strips of a parallel-strip barrier; and

shifting to the left or to the right, in relation to the strips of the barrier, the patterns of the first and second images by a number of image pixels or sub-pixels as a function of a position of a viewer of the stereoscopic image.

2. The method of claim 1, comprising:

determining the position of the viewer by tracking the eyes of the viewer;

measuring a distance between the eyes of the viewer; and

dimming one or more image pixels or sub-pixels if the distance between the eyes of the viewer in relation to a distance between the viewer and the barrier is less than a threshold where left and right image pixels or sub-pixels start to overlap as seen from the eyes of the viewer.

3. The method of claim 1, wherein:

the first image is generated during a first of two timeslots;

the second image is generated during a second of the two timeslots;

alternating strips of the barrier open and close at successive timeslots;

the strips of the barrier are divided into sub-strips;

the strips of the barrier are in continuous motion; and

the patterns of the first and second images track the continuous motion of the strips of the barrier.

4. The method of claim 3, wherein the strips of the barrier are shifted sideways by 1 or more sub-strips once every 1 or 2 timeslots.

5. The method of claim 1, wherein:

the first image is generated during a first of two timeslots;

the second image is generated during a second of the two timeslots;

alternating strips of the barrier open and close at successive timeslots;

the method further comprising adjusting the number N of pixels or sub-pixels in the first and second image patterns based on a distance between the viewer and the stereoscopic image.

6. The method of claim 1, wherein:

the first image is generated during a first of two timeslots;

the second image is generated during a second of the two timeslots;

alternating strips of the barrier open and close at successive timeslots;

the method further comprising;

generating a composite image having, for each sub-pixel, a highest common luminance of corresponding sub-pixels of left and right images;

generating the first image by subtracting, from each sub-pixel of the left image, a luminance of a corresponding sub-pixel of the composite image;

generating the second image by subtracting, from each sub-pixel of the right image, a luminance of a corresponding sub-pixel of the composite image; and

displaying the first image, the second image and the composite image over three successive timeslots;

wherein the composite image is displayed without blocking.

7. The method of claim 1, wherein:

the first image is generated during a first of two timeslots;

the second image is generated during a second of the two timeslots;

alternating strips of the barrier open and close at successive timeslots;

the method further comprising;

measuring a distance between the stereoscopic image and the viewer'"'"'s left eye;

measuring a distance between the stereoscopic image and the viewer'"'"'s right eye;

if the right eye is further away than the left eye, varying the number N of pixels or sub-pixels per columns the first and second image patterns, over a width of the first and second images, so that an increasing value of N is used from the left to the right of the first and second images; and

if the right eye is closer than the left eye, varying the number N of pixels or sub-pixels per columns in the first and second image patterns, over the width of the first and second images, so that a decreasing value of N is used from the left to the right of the first and second images.

8. The method of claim 1, wherein the strips of the barrier are rotated axially, in relation to the columns of the first and second image patterns, in a range of 5 to 35 degrees of rotation.

9. The method of claim 1, wherein:

the first and second images have orthogonal polarizations; and

alternating strips of the barrier have orthogonal polarizations.

10. A display for showing a stereoscopic image, comprising:

a screen for generating a first image having a pattern comprising alternating columns of N left-image pixels or sub-pixels and of N right-image pixels or sub-pixels and for generating a second image having a reversed pattern from the pattern of the first image;

a parallel-strip barrier having alternating strips for blocking alternating columns of the first and second images;

a tracking system for tracking a position of a viewer of the stereoscopic image; and

a controller of the screen for shifting to the left or to the right, in relation to the strips of the barrier, the patterns of the first and second images by a number of image pixels or sub-pixels as a function of the position of the viewer.

11. The display of claim 10, wherein:

N is equal to 12 image sub-pixels;

the screen has a 1920-pixel horizontal resolution over a width of about 60 cm;

the barrier is positioned about 1 cm from the screen; and

a planned distance between the display and the viewer is about 60 cm;

whereby no shifting of the patterns of the first and second images occurs when the viewer is substantially positioned at the planned distance and substantially centered with the stereoscopic image.

12. The display of claim 10, wherein the barrier is placed in front of the screen.

13. The display of claim 10, wherein:

the screen is configured to generate the first and second images at orthogonal polarizations; and

alternating strips of the barrier have orthogonal polarizations.

14. The display of claim 10, wherein:

the screen is configured to generate the first image during a first of two timeslots;

the screen is configured to generate the second image during a second of the two timeslots; and

the barrier is configured to open and close alternating strips at successive timeslots; and

the screen is placed in front of the barrier.

15. The display of claim 10, wherein:

the screen is configured to generate the first image during a first of two timeslots;

the screen is configured to generate the second image during a second of the two timeslots;

the barrier is configured to open and close alternating strips at successive timeslots; and

the strips of the barrier are divided into sub-strips.

16. The display of claim 15, wherein the controller is configured to adjust a width of the strips of the barrier by associating a number of sub-strips.

17. The display of claim 15, wherein:

the barrier is configured to move its strips in continuous motion; and

the controller of the screen is configured to track the continuous motion of the strips of the barrier.

18. The display of claim 17, wherein the barrier is configured to shift its strips sideways by 1 or more sub-strips once every 1 or 2 timeslots.

19. The display of claim 10, wherein:

the screen is configured to generate the first image during a first of two timeslots;

the screen is configured to generate the second image during a second of the two timeslots; and

the barrier is configured to open and close alternating strips at successive timeslots;

the display further comprising;

an image source configured to;

provide to the screen a composite image having, for each sub-pixel, a highest common luminance of corresponding sub-pixels of left and right images;

provide the first image to the screen by subtracting, from each sub-pixel of the left image, a luminance of a corresponding sub-pixel of the composite image;

provide the second image to the screen by subtracting, from each sub-pixel of the right image, a luminance of a corresponding sub-pixel of the composite image;

wherein;

the screen is configured to display the first image, the second image and the composite image over three successive timeslots; and

the parallel-strip barrier is configured to pass the composite image without blocking.

20. The display of claim 10, wherein:

the screen is configured to generate the first image during a first of two timeslots;

the screen is configured to generate the second image during a second of the two timeslots;

the barrier is configured to open and close alternating strips at successive timeslots;

the tracking system is configured to determine a distance between the stereoscopic image and the viewer'"'"'s left eye and to determine a distance between the stereoscopic image and the viewer'"'"'s right eye; and

the controller is configured to vary N over a width of the display so that;

if the right eye is further away than the left eye, an increasing value of N is used from the left to the right of the display; and

if the right eye is closer than the left eye, a decreasing value of N is used from the left to the right of the display.