Blended autofocus using mechanical and softlens technologies
A blended approach to achieving best system-level autofocus in a camera module where conventional mechanical autofocus techniques (and their associated filter algorithms) are used in conjunction with softlens autofocus techniques. In this manner, the mechanical autofocus approach needs only get close to the best focus position (thereby relaxing its tolerances) and then the softlens autofocus approach takes over and completes the fine tuning of the best focus (thereby relaxing its capabilities requirements).
1 . A method of using blended autofocusing using mechanical and softlens autofocusing, comprising the steps of:
a) performing mechanical autofocusing to within an acceptable autofocus step size tolerance;
b) capturing an image;
c) pre-processing said image using a constrained softlens autofocus processing algorithm having a simplified version of a softlens autofocus processing algorithm by:
I. performing refocus-range-limited softlens autofocus processing; and
d) handing off said pre-processed output image to the rest of an image processing pipeline.
2 . The method of claim 1 , wherein step c) further comprises:
II. performing additional softlens autofocus processing in image regions that are affected by tip;
III. performing additional softlens autofocus processing in image regions that are affected by tilt; and
IV. performing additional softlens autofocus processing in image regions that are affected by Petzval curvature.
3 . The method of claim 2 , wherein said step c) further comprises a step V:
V. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
4 . The method of claim 3 , wherein said acceptable step size tolerance is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
5 . The method of claim 3 , wherein said range-range limited softlens autofocus processing algorithm does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
6 . The method of claim 3 , wherein said simplified softlens autofocus processing algorithm performs only over the bounds between two mechanical autofocus steps.
7 . The method of claim 3 , wherein said refocus-range-limited softlens autofocus processing algorithm need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
8 . The method of claim 3 , wherein said softlens autofocus processing algorithm is constrained by user preference.
9 . The method of claim 3 , wherein said softlens autofocus processing algorithm is constrained by the type of camera system used.
10 . The method of claim 3 , wherein depth of field tuning after image capture is achieved by varying in software the strength of said softlens autofocus processing algorithm.
11 . The method of claim 1 , wherein said step c) further comprises a step II:
II. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
12 . The method of claim 11 , wherein said acceptable step size tolerance is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
13 . The method of claim 11 , wherein said range-range limited softlens autofocus processing algorithm does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
14 . The method of claim 11 , wherein said simplified softlens autofocus processing algorithm performs only over the bounds between two mechanical autofocus steps.
15 . The method of claim 11 , wherein said refocus-range-limited softlens autofocus processing algorithm need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
16 . The method of claim 11 , wherein said softlens autofocus processing algorithm is constrained by user preference.
17 . The method of claim 11 , wherein said softlens autofocus processing algorithm is constrained by the type of camera system used.
18 . The method of claim 11 , wherein depth of field tuning after image capture is achieved by varying in software the strength of said softlens autofocus processing algorithm.
19 . A method of using blended autofocusing using mechanical and softlens autofocusing, comprising the steps of:
a) performing mechanical autofocusing to within an acceptable autofocus step size tolerance;
b) capturing an image;
c) pre-processing said image using a constrained softlens autofocus processing algorithm having a simplified version of a softlens autofocus processing algorithm by:
I. performing refocus-range-limited softlens autofocus processing;
d) handing off said pre-processed output image to the rest of an image processing pipeline;
e) performing additional location-specific processing by:
I. refining the focus where tip makes blur worse in those regions that do not suffer from defocus;
II. refining the focus where tilt makes blur worse in those regions that do not suffer from defocus;
III. performing additional location-specific processing to refine the focus where Petzval curvature make blur worse in those regions that do not suffer from defocus;
IV. deconvolving blur from a section of defocused area of said image; and
V. varying the softlens autofocus strength depending on known mechanical autofocus limitations across the image plane.
20 . The method of claim 19 , wherein step c) further comprises:
II. performing additional softlens autofocus processing in image regions that are affected by tip;
III. performing additional softlens autofocus processing in image regions that are affected by tilt; and
IV. performing additional softlens autofocus processing in image regions that are affected by Petzval curvature.
21 . The method of claim 20 , wherein said step c) further comprises a step V:
V. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
22 . The method of claim 21 , wherein said acceptable autofocus step size tolerance of step a) is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
23 . The method of claim 21 , wherein step c)I does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
24 . The method of claim 21 , wherein step c) performs only over the bounds between two mechanical autofocus steps.
25 . The method of claim 21 , wherein step c)I need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
26 . The method of claim 21 , wherein said softlens autofocus processing algorithm is constrained by user preference.
27 . The method of claim 21 , wherein said softlens autofocus processing algorithm is constrained by the type of camera system used.
28 . The method of claim 21 , wherein depth of field tuning after image capture is achieved by varying in software the strength of said softlens autofocus processing algorithm.
29 . The method of claim 19 , wherein said step c) further comprises a step II:
II. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
30 . The method of claim 29 , wherein said acceptable autofocus step size tolerance of step a) is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
31 . The method of claim 29 , wherein step c)I does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
32 . The method of claim 29 , wherein step c) performs only over the bounds between two mechanical autofocus steps.
33 . The method of claim 29 , wherein step c)I need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
34 . The method of claim 29 , wherein said softlens autofocus processing algorithm is constrained by user preference.
35 . The method of claim 29 , wherein said softlens autofocus processing algorithm is constrained by the type of camera system used.
36 . The method of claim 29 , wherein depth of field tuning after image capture is achieved by varying in software the strength of said softlens autofocus processing algorithm.
37 . A method of using blended autofocusing using mechanical and softlens autofocusing, comprising the steps of:
a) performing mechanical autofocusing to within an acceptable autofocus step size tolerance;
b) capturing an image;
c) pre-processing said image using a constrained softlens autofocus processing algorithm having a simplified version of a softlens autofocus processing algorithm by:
I. performing refocus-range-limited softlens autofocus processing;
d) handing off said pre-processed output image to the rest of an image processing pipeline;
e) performing additional location-specific processing by:
I. refining the focus where tip makes blur worse in those regions that do not suffer from defocus;
II. performing additional location-specific processing to refine the focus where tilt makes blur worse in those regions that do not suffer from defocus;
III. performing additional location-specific processing to refine the focus where Petzval curvature make blur worse in those regions that do not suffer from defocus;
IV. deconvolving blur from a section of defocused area of said image;
f) Selection of depth at which a user wishes said image to be at best focus; and
g) Selection by the user of the overall depth of focus in said image.
38 . The method of claim 37 , wherein step c) further comprises:
II. performing additional softlens autofocus processing in image regions that are affected by tip;
III. performing additional softlens autofocus processing in image regions that are affected by tilt; and
IV. performing additional softlens autofocus processing in image regions that are affected by Petzval curvature.
39 . The method of claim 38 , wherein said step c) further comprises a step V:
V. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
40 . The method of claim 39 , wherein said softlens autofocus processing algorithm is constrained by user preference.
41 . The method of claim 39 , wherein said softlens autofocus processing algorithm is camera system constrained.
42 . The method of claim 39 , wherein said acceptable autofocus step size tolerance of step a) is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
43 . The method of claim 39 , wherein step c)I does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
44 . The method of claim 39 , wherein step c) performs only over the bounds between two mechanical autofocus steps.
45 . The method of claim 39 , wherein step c)I need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
46 . The method of claim 39 , wherein a camera preset or presets are used in place of step f).
47 . The method of claim 39 , wherein a camera preset or presets are used in place of step g).
48 . The method of claim 37 , wherein said step c) further comprises a step II:
II. constraining said softlens autofocus processing to achieve a preferred depth of field-look in an output image.
49 . The method of claim 48 , wherein said softlens autofocus processing algorithm is constrained by user preference.
50 . The method of claim 48 , wherein said softlens autofocus processing algorithm is camera system constrained.
51 . The method of claim 48 , wherein said acceptable autofocus step size tolerance of step a) is close enough to the correct focus such that a concurrent softlens autofocus processing can complete a next focus action.
52 . The method of claim 48 , wherein step c)I does not include an entire object distance range, but rather a focus range that is within the bounds of said mechanical autofocusing steps.
53 . The method of claim 48 , wherein step c) performs only over the bounds between two mechanical autofocus steps.
54 . The method of claim 48 , wherein step c)I need only refocus a camera system within a limited range of two neighboring mechanical autofocus steps.
55 . The method of claim 48 , wherein a camera preset or presets are used in place of step f).
56 . The method of claim 48 , wherein a camera preset or presets are used in place of step g).