US6320979B1
Expired / Lapsed
US
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Depth of field enhancement
Assignee: Canon Inc
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Filing: 1998-10-06
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Granted: 2001-11-20
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Expires: 2018-10-06
Abstract
Abstract A lens system ( 100 ) and image plane ( 104 ) are used to capture a number of sample images ( 400 ) of a three dimensional scene, each sample image ( 400 ) corresponding to a different object distance ( 106 ). The in-focus portions of each of the sample images ( 400 ) are then merged into a composite image ( 620 ) which appears to have a depth of field greater than any of the sample images ( 400 ). In one embodiment, the lens system ( 100 ) is movably attached to a camera housing ( 302 ) such that a motor ( 304 ) can move the lens system ( 100 ) in the direction of the central axis of the lens system ( 100 ). A two dimensional array ( 300 ) of photo-sensors is mounted in the camera along the central axis of the lens system ( 100 ). As the lens system ( 100 ) is traversed along the central axis, points at various distances in front of the lens system ( 100 ) pass in and out of focus on the array ( 300 ) of photo-sensors. Image information is captured from the array ( 300 ) as it is traversed, producing a series of depth-differentiated sample images ( 400 ). The in-focus portion of each sample image ( 400 ) is identified through contrast analysis. The in-focus portions identified are added to produce a composite image ( 620 ) of the scene exhibiting an apparently large depth of field.
Inventors
- 👤 Roger D. Melen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:45
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/0075; G02B21/00; G02B21/36; G02B21/365; G02B21/367; G06; G06T; G06T5/00; G06T5/50; H; H04; H04N; H04N23/00; H04N23/50; H04N23/55; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
182 words
A method for using an imaging system and an array of sensor locations to construct a composite image of a three dimensional scene, the array of sensor locations defining an image plane on which is focused an image of points a focus distance in front of the image plane, the method comprising the steps of: moving the imaging system relative to the image plane so as to change the focus distance; at each sensor location of the array, for at least two distinct focus distances: sensing radiation which has passed through the imaging system; producing image information based on the sensed radiation including a brightest pixel value and a darkest pixel value; calculating a contrast value as a ratio of the brightest pixel value within the sensor location to the darkest pixel value within the sensor location; and assigning the calculated contrast value to a plurality of pixels within the sensor location; recording the image information; and constructing a composite image by incorporating into said composite image, for each sensor location, image information from that focus distance which produces the maximum contrast.
Claim 2
Independent Claim
182 words
A method for using an imaging system and an array of sensor locations to construct a composite image of a three dimensional scene, the array of sensor locations defining an image plane on which is focused an image of points a focus distance in front of the image plane, the method comprising the steps of: moving the imaging system relative to the image plane so as to change the focus distance; at each sensor location of the array, for at least two distinct focus distances: sensing radiation which has passed through the imaging system; producing image information based on the sensed radiation including a brightest pixel value and a darkest pixel value; calculating a contrast value as a ratio of the brightest pixel value within the sensor location to the darkest pixel value within the sensor location; and assigning the calculated contrast value to a plurality of pixels within the sensor location; recording the image information; and constructing a composite image by incorporating into said composite image, for each sensor location, image information from that focus distance which produces the maximum contrast.
Claim 3
Dependent Claim
20 words
The method of claim 1 , wherein the imaging system comprises one of a lens system and a mirror system.
Claim 4
Dependent Claim
14 words
The method of claim 1 , wherein the imaging system comprises a convex lens.
Claim 5
Dependent Claim
33 words
The method of claim 1 , wherein the radiation is sensed at each sensing location by one of a Charge Coupled Device (CCD) cell, a photosensitive film region, and an X-ray film region.
Claim 6
Dependent Claim
17 words
The method of claim 1 , wherein the radiation is one of visible light and X-ray radiation.
Claim 7
Dependent Claim
33 words
The method of claim 1 wherein the radiation is sensed by photosensitive film, and a separate frame of film is exposed for each position of the imaging system relative to the image plane.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein each sensor location contains at least one pixel that is also contained within at least one other sensor location.
Claim 9
Independent Claim
141 words
A method for using at least two sample images of a three dimensional scene to construct a composite image of the scene, each of the sample images corresponding to a unique focus distance, the method comprising the steps of: for each sample image and for each of at least two measurement regions, each measurement region corresponding to a portion of the scene represented in the sample images, determining contrast information as a ratio of a brightest pixel value within each measurement region to a darkest pixel value within each measurement region, and assigning the contrast value to a plurality of pixels within each measurement region; and combining image information from all of the sample images, on a measurement region by measurement region basis, based upon which sample image exhibits the maximum contrast for that measurement region, to construct the composite image.
Claim 10
Independent Claim
141 words
A method for using at least two sample images of a three dimensional scene to construct a composite image of the scene, each of the sample images corresponding to a unique focus distance, the method comprising the steps of: for each sample image and for each of at least two measurement regions, each measurement region corresponding to a portion of the scene represented in the sample images, determining contrast information as a ratio of a brightest pixel value within each measurement region to a darkest pixel value within each measurement region, and assigning the contrast value to a plurality of pixels within each measurement region; and combining image information from all of the sample images, on a measurement region by measurement region basis, based upon which sample image exhibits the maximum contrast for that measurement region, to construct the composite image.
Claim 11
Dependent Claim
13 words
The method of claim 8 , wherein the sample images are digital images.
Claim 12
Dependent Claim
13 words
The method of claim 8 , wherein the sample images are photographic images.
Claim 13
Dependent Claim
13 words
The method of claim 8 , wherein the method is a computer-implemented method.
Claim 14
Dependent Claim
160 words
A computer-readable medium containing a computer program for using at least two sample images of a three dimensional scene to construct a composite image of the scene, each of the sample images corresponding to a unique focus distance, the computer program comprising an array of instructions for causing a central processing unit (CPU) to perform the steps of: for each sample image and for each of at least two measurement regions, each measurement region corresponding to a portion of the scene represented in the sample images, determining contrast information as a ratio of a brightest pixel value within each measurement region to a darkest pixel value within each measurement region, and assigning the contrast value to a plurality of pixels within each measurement region; and combining image information from all of the sample images, on a measurement region by measurement region basis, based upon which sample image exhibits the maximum contrast for that measurement region, to construct the composite image.
Claim 15
Dependent Claim
160 words
A computer-readable medium containing a computer program for using at least two sample images of a three dimensional scene to construct a composite image of the scene, each of the sample images corresponding to a unique focus distance, the computer program comprising an array of instructions for causing a central processing unit (CPU) to perform the steps of: for each sample image and for each of at least two measurement regions, each measurement region corresponding to a portion of the scene represented in the sample images, determining contrast information as a ratio of a brightest pixel value within each measurement region to a darkest pixel value within each measurement region, and assigning the contrast value to a plurality of pixels within each measurement region; and combining image information from all of the sample images, on a measurement region by measurement region basis, based upon which sample image exhibits the maximum contrast for that measurement region, to construct the composite image.
Claim 16
Dependent Claim
14 words
The computer-readable medium of claim 12 , wherein the sample images are digital images.
Claim 17
Dependent Claim
14 words
The computer-readable medium of claim 12 , wherein the sample images are photographic images.
Claim 18
Independent Claim
233 words
A system for constructing a composite image of a three dimensional scene, the system comprising: an array of sensor locations defining an image plane, each sensor location being adapted for sensing radiation, and for producing radiation information including a brightest pixel value and a darkest pixel value; an imaging system for focusing on the image plane an image of points a focus distance away from the image plane, the imaging system being movably coupled to the array such that the array is mounted along an d generally orthogonal to a central axis of the imaging system; a motor coupled to the imaging system and to the array for, in response to a command signal, changing the distance between the imaging system and the array, such as to change the focus distance; and a processor module coupled to the array and to the motor, for: sending command signals to the motor to cause it to change the focus distance; receiving radiation information from each of the sensor locations; and constructing a composite image by calculating a contrast value as a ratio of the brightest pixel value within the sensor location to the darkest pixel value within the sensor location, assigning the calculated contrast value to a plurality of pixels within the sensor location, and incorporating into said composite image, for each sensor location, radiation information from that focus distance which produces the maximum contrast.
Claim 19
Independent Claim
233 words
A system for constructing a composite image of a three dimensional scene, the system comprising: an array of sensor locations defining an image plane, each sensor location being adapted for sensing radiation, and for producing radiation information including a brightest pixel value and a darkest pixel value; an imaging system for focusing on the image plane an image of points a focus distance away from the image plane, the imaging system being movably coupled to the array such that the array is mounted along an d generally orthogonal to a central axis of the imaging system; a motor coupled to the imaging system and to the array for, in response to a command signal, changing the distance between the imaging system and the array, such as to change the focus distance; and a processor module coupled to the array and to the motor, for: sending command signals to the motor to cause it to change the focus distance; receiving radiation information from each of the sensor locations; and constructing a composite image by calculating a contrast value as a ratio of the brightest pixel value within the sensor location to the darkest pixel value within the sensor location, assigning the calculated contrast value to a plurality of pixels within the sensor location, and incorporating into said composite image, for each sensor location, radiation information from that focus distance which produces the maximum contrast.
Claim 20
Dependent Claim
20 words
The system of claim 15 , wherein the imaging system comprises one of a lens system and a mirror system.
Claim 21
Dependent Claim
33 words
The system of claim 15 , wherein the radiation is sensed at each sensing location by one of a Charge Coupled Device (CCD) cell, a photosensitive film region, and an X-ray film region.
Claim 22
Dependent Claim
17 words
The system of claim 15 , wherein the radiation is one of visible light and X-ray radiation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-11-19 | 2005-05-21 | 2005-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-11-19 | 2009-05-21 | 2009-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-11-19 | 2013-05-21 | 2013-11-20 | $7700.00 | Window Closed / Lapsed |