Stereoscopic depth mapping
View Patent ↗Provided is a method and apparatus for linear depth mapping. Linear depth mapping includes using algorithms to correct the distorted depth mapping of stereoscopic capture and display systems.
1. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining a minimum separation between the left image and the right image for a nearest object in the stereoscopic image;
determining a maximum separation between the left image and the right image for a most distant object in the stereoscopic image; and
calculating the camera separation distance based on the minimum separation of the nearest object and the maximum separation of the most distant object;
wherein calculating the camera separation distance comprises using an equation in which:
A
=
2
·
tan
θ
·
Z
max
·
Z
min
·
(
Ds
max
-
Ds
min
)
W
·
(
Z
max
-
Z
min
)
.
2. The method of claim 1 , further comprising:
calculating a fixed disparity based on the minimum separation and the maximum separation.
3. The method of claim 2 , wherein calculating the fixed disparity comprises using the equation:
D
=
(
Z
max
·
Ds
max
-
Z
min
·
Ds
min
)
(
Z
max
-
Z
min
)
.
4. The method of claim 1 , wherein the minimum separation and the maximum separation correspond to scaled-depth mapping.
5. The method of claim 4 , wherein a perceived depth of the scene is directly proportional to an actual depth of the scene.
6. The method of claim 4 , wherein a scaled-depth mapping condition is met, the scaled-depth mapping condition comprises:
Ds
min
≥
Z
max
·
Ds
max
-
(
Z
max
-
Z
min
)
·
E
Z
min
.
7. The method of claim 1 , wherein calculating the camera separation distance comprises determining the camera separation distance as a function of depth of an object in the scene.
8. The method of claim 7 wherein determining the camera separation distance as a function of depth comprises determining the camera separation using a linear mapping equation.
9. The method of claim 8 , wherein the linear mapping equation comprises:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
.
10. A method for positioning cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the method comprising:
determining whether a scaled-depth mapping condition is met using an equation in which:
Ds
min
≥
Z
max
·
Ds
max
-
(
Z
max
-
Z
min
)
·
E
Z
min
;
and
applying the scaled-depth mapping, whereby throughout the scene, a perceived depth of the scene is set directly proportional to an actual depth of the scene.
11. The method of claim 10 , further comprising determining a camera separation distance between the cameras.
12. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining the camera separation distance as a function of depth of an object in the scene using a linear mapping equation in which:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
.
13. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining whether a scaled-depth mapping condition is met;
if the scaled-depth mapping condition is met, applying the scaled-depth mapping, whereby throughout the scene, a perceived depth of the scene is set directly proportional to an actual depth of the scene; and
if the scaled-depth mapping condition is not met, setting the camera separation distance as a function of depth of an object in the scene;
wherein determining whether the scaled-depth mapping condition is met comprises using an equation in which:
Ds
min
≥
Z
max
·
Ds
max
-
(
Z
max
-
Z
min
)
·
E
Z
min
.
14. The method of claim 13 , wherein setting the camera separation distance as a function of depth comprises determining the camera separation using a linear mapping equation.
15. The method of claim 14 , wherein the linear mapping equation comprises:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
.
16. The method of claim 13 , further comprising determining the camera separation distance if the scaled-depth mapping condition is met.
17. A method for providing a stereoscopic image of a scene comprising a left image and a right image, the left image having left image pixels and the right image having corresponding right image pixels, the method comprising:
determining a camera separation distance between a first and second camera position;
adjusting an actual disparity of pixels in a captured image pair to provide a desired disparity for the left image pixels and the right image pixels; and
determining the desired disparity using an equation in which:
Δ
D
(
Ds
)
=
Ds
-
Ds
n
=
Ds
-
(
2
·
Ds
·
tan
θ
·
s
-
2
·
Ds
·
tan
θ
·
β
-
2
·
D
·
tan
θ
·
s
+
2
·
D
·
tan
θ
·
β
+
A
·
W
·
α
)
·
E
(
2
·
D
·
tan
θ
·
β
+
A
·
W
·
α
-
2
·
Ds
·
tan
θ
·
β
)
.
18. The method of claim 17 , wherein adjusting the actual disparity to provide the desired disparity comprises correcting for non-linear mapping.
19. The method of claim 17 , wherein the actual disparity comprises an offset between a left and right eye image of the captured image pair.
20. The method of claim 17 , wherein the desired disparity comprises an offset between the left image pixels and the right image pixels of the stereoscopic image of the scene.
21. The method of claim 17 , further comprising back-filling the stereoscopic image of the scene.
22. A method for positioning first and second cameras for capturing one or more stereoscopic image frames, each stereoscopic image frame comprising a left image and a right image, and the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining a current frame position and direction;
calculating a camera spacing profile A(Z) for the current frame using an equation in which:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
;
calculating a fixed disparity D based on a desired disparity budget for the current frame;
capturing left and right images for the current frame using varying camera positions based on the camera spacing profile; and
cropping and shifting the left and right images for the current frame based on the fixed disparity D.
23. The method of claim 22 , further comprising buffering the left and right images for the current frame.
24. The method of claim 23 , further comprising repeating the determining, calculating, capturing, cropping and shifting, and buffering for a plurality of consecutive stereoscopic image frames.
25. The method of claim 22 , wherein calculating the fixed disparity D comprises using the equation:
D
=
(
Z
max
·
Ds
max
-
Z
min
·
Ds
min
)
(
Z
max
-
Z
min
)
.
26. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining a minimum separation between the left image and the right image for a nearest object in the stereoscopic image;
determining a maximum separation between the left image and the right image for a most distant object in the stereoscopic image;
calculating the camera separation distance based on the minimum separation of the nearest object and the maximum separation of the most distant object; and
calculating a fixed disparity based on the minimum separation and the maximum separation using an equation in which:
D
=
(
Z
max
·
Ds
max
-
Z
min
·
Ds
min
)
(
Z
max
-
Z
min
)
.
27. The method of claim 26 , wherein the minimum separation and the maximum separation correspond to scaled-depth mapping.
28. The method of claim 27 , wherein a perceived depth of the scene is directly proportional to an actual depth of the scene.
29. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining a minimum separation between the left image and the right image for a nearest object in the stereoscopic image;
determining a maximum separation between the left image and the right image for a most distant object in the stereoscopic image; and
calculating the camera separation distance based on the minimum separation of the nearest object and the maximum separation of the most distant object;
wherein calculating the camera separation distance comprises determining the camera separation distance as a function of depth of an object in the scene using a linear mapping equation in which:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
.
30. The method of claim 29 , wherein the minimum separation and the maximum separation correspond to scaled-depth mapping.
31. The method of claim 30 , wherein a perceived depth of the scene is directly proportional to an actual depth of the scene.
32. A method for positioning first and second cameras for capturing a stereoscopic image of a scene comprising a left image and a right image, the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining whether a scaled-depth mapping condition is met;
if the scaled-depth mapping condition is met, applying the scaled-depth mapping, whereby throughout the scene, a perceived depth of the scene is set directly proportional to an actual depth of the scene; and
if the scaled-depth mapping condition is not met, setting the camera separation distance as a function of depth of an object in the scene;
wherein setting the camera separation distance comprises determining the camera separation using a linear mapping equation in which:
A
(
Z
)
=
2
·
tan
θ
W
·
(
D
-
E
)
·
Z
+
2
·
tan
θ
·
s
·
E
·
Z
W
·
(
α
·
Z
+
β
)
.
33. The method of claim 32 , further comprising determining the camera separation distance if the scaled-depth mapping condition is met.
34. A method for positioning first and second cameras for capturing one or more stereoscopic image frames, each stereoscopic image frame comprising a left image and a right image, and the first and second cameras being spaced apart by a camera separation distance, the method comprising:
determining a current frame position and direction;
calculating a camera spacing profile A(Z) for the current frame;
calculating a fixed disparity D based on a desired disparity budget for the current frame using an equation in which:
D
=
(
Z
max
·
Ds
max
-
Z
min
·
Ds
min
)
(
Z
max
-
Z
min
)
;
capturing left and right images for the current frame using varying camera positions based on the camera spacing profile;
cropping and shifting the left and right images for the current frame based on the fixed disparity D.