US2014031680A1PendingUtilityA1
Otoscanner With 3D Imaging And Onboard Tracking
Est. expiryMar 12, 2032(~5.7 yrs left)· nominal 20-yr term from priority
Inventors:Nathanael BerglundHarris BergmanScott C. CahallJerry FosterEohan GeorgeSamuel W. HarrisGiorgos HatziliasKarol Constantine HatziliasRuizhi HongWess Eric SharpeDavid G. StitesHarry S. Strothers, Iv
A61B 1/227B33Y 80/00A61B 5/0073A61B 2034/2055A61B 5/7253A61B 1/00052A61B 2090/367A61B 5/1079A61B 5/0062A61B 5/065
53
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Claims
Abstract
Apparatus and methods for tracking scanner motion with a tracking illumination emitter mounted on a scanner, the scanner including imaging apparatus that captures a sequence of images of a scanned object as the scanner moves with respect to the scanned object; tracking targets installed off the scanner at positions that are fixed relative to a scanned object; one or more tracking illumination sensors mounted on the scanner, the tracking illumination sensors sensing reflections of tracking illumination emitted from the tracking illumination emitter and reflected from the tracking targets as the scanner moves in the process of scanning the scanned object; and one or more data processors, at least one of the data processors coupled for data communications to the tracking illumination sensors, the data processor determining, as the scanner moves, tracked positions of the scanner based upon values of the reflections.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A tracker for scanner motion, the tracker comprising:
a tracking illumination emitter mounted on a scanner, the scanner including imaging apparatus that captures a sequence of images of a scanned object as the scanner moves with respect to the scanned object; tracking targets installed off the scanner at positions that are fixed relative to a scanned object; one or more tracking illumination sensors mounted on the scanner, the tracking illumination sensors sensing reflections of tracking illumination emitted from the tracking illumination emitter and reflected from the tracking targets as the scanner moves in the process of scanning the scanned object; and one or more data processors, at least one of the data processors coupled for data communications to the tracking illumination sensors, the data processor determining, as the scanner moves, tracked positions of the scanner based upon values of the reflections.
2 . The tracker of claim 1 further comprising at least one of the processors configured so that it:
determines the position of the scanner in object space when the scanner is positioned at a predetermined position with respect to the scanned object; and
sets the position of the scanner at the predetermined position as the origin of a coordinate system defining object space.
3 . The tracker of claim 1 wherein the scanned object is an ear, and the tracker further comprises at least one of the processors configured so that it:
determines the position of the scanner in object space when the probe is positioned at the aperture of the auditory canal of the scanned ear; and
sets the position of the scanner at the aperture of the auditory canal of the scanned ear as the origin of a coordinate system defining object space.
4 . The tracker of claim 1 wherein the tracking targets comprise retroreflectors.
5 . The tracker of claim 1 wherein the tracking illumination is infrared light.
6 . The tracker of claim 1 further comprising at least one of the data processors configured so that it constructs a 3D image of the scanned object based upon the sequence of images and the tracked positions of the scanner.
7 . The tracker of claim 1 further comprising at least one of the data processors configured so that it constructs a 3D image based upon the sequence of images and the tracked positions of the scanner, with the sequence of images implemented as a sequence of 2D images, including, for the sequence of 2D images from the image sensor of the object taken when the object is illuminated by imaging light from the scanner:
detecting ridge points for each 2D image, including identifying a set of brightest pixels for each 2D image, each set depicting a c-shaped broken ring of imaging light reflecting from a surface of the scanned object;
transforming, in dependence upon a predefined association between each pixel in the image sensor and corresponding points in scanner space, the ridge points to points in scanner space; and
transforming, in dependence upon a relationship between an origin of a coordinate system defining scanner space and an origin of another coordinate system defining object space, the points in scanner space to points in object space.
8 . The tracker of claim 1 further comprising at least one of the data processors configured so that it constructs a 3D image based upon the sequence of images and the tracked positions of the scanner, including:
establishing, for each scanned image, transforming tensor values for a transforming tensor that expresses a relationship between a coordinate system defining object space and a coordinate system defining scanner space; and
transforming locations in scanner space of imaging pixels from each scanned image to corresponding scanned points in object space, the transforming carried out with the transforming tensor according to:
[
x
′
y
′
z
′
1
]
≡
[
R
11
R
12
R
13
T
1
R
21
R
22
R
23
T
2
R
31
R
32
R
33
T
3
0
0
0
1
]
[
x
y
z
1
]
,
wherein:
the T values in the tensor express the translation of scanner space with respect to object space,
the R values express the rotation of scanner space with respect to object space, vector x,y,z represents a location of an imaging pixel in scanner space, and vector x′,y′,z′ represents a location of scanned point in object space that corresponds to the location x,y,z in scanner space.
9 . The tracker of claim 8 wherein the scanned object is an ear, and the object space is taken as ear space.
10 . The tracker of claim 1 wherein the imaging apparatus further comprises a probe comprising a wide-angle lens optically coupled to an image sensor and an imaging light source, with the lens configured so that it conducts reflected imaging illumination from the scanned object to the image sensor, the image sensor is operably coupled to at least one of the processors, and the image sensor under processor control captures the sequence of images.
11 . The tracker of claim 1 further comprising components of the imaging apparatus that include a probe that in turn includes a wide-angle lens optically coupled to an image sensor, and an imaging light source, with the lens configured so that it conducts to the image sensor imaging illumination emitted by the imaging light source and reflected from the scanned object, the image sensor being coupled for data communications to at least one of the data processors, the imaging sensor capturing the sequence of images, and the at least one of the data processors constructs, in dependence upon the sequence of images from the sensor and the tracked positions of the scanner, a 3D image of the scanned object.
12 . A method of tracking scanner motion, the method comprising:
capturing by imaging apparatus of a scanner a sequence of images of a scanned object as the scanner moves with respect to the scanned object, the scanned object illuminated by tracking illumination from a tracking illumination emitter mounted on the scanner, sensing, by one or more tracking illumination sensors mounted on the scanner as the scanner moves in the process of scanning the scanned object, reflections of tracking illumination emitted from the tracking illumination emitter and reflected from tracking targets installed off the scanner at positions that are fixed relative to the scanned object; determining, by one or more data processors coupled for data communications to the tracking illumination sensors, as the scanner moves, tracked positions of the scanner based upon values of the reflections.
13 . The method of claim 12 further comprising:
determining by the one or more data processors the position of the scanner in object space when the scanner is positioned at a predetermined position with respect to the scanned object; and
setting by the one or more data processors the position of the scanner at the predetermined position as the origin of a coordinate system defining object space.
14 . The method of claim 12 wherein the scanned object is an ear, and the method further comprises:
determining by the one or more data processors the position of the scanner in object space when the probe is positioned at the aperture of the auditory canal of the scanned ear; and
setting by the one or more data processors the position of the scanner at the aperture of the auditory canal of the scanned ear as the origin of a coordinate system defining object space.
15 . The method of claim 12 wherein the tracking targets comprise retroreflectors.
16 . The method of claim 12 wherein the tracking illumination is infrared light.
17 . The method of claim 12 further comprising constructing by the one or more data processors a 3D image of the scanned object based upon the sequence of images and the tracked positions of the scanner.
18 . The method of claim 12 further comprising constructing by the one or more data processors a 3D image of the scanned object based upon the sequence of images and the tracked positions of the scanner, with the sequence of images implemented as a sequence of 2D images, including, for the sequence of 2D images from the image sensor of the object taken when the object is illuminated by imaging light from the scanner:
detecting ridge points for each 2D image, including identifying a set of brightest pixels for each 2D image, each set depicting a c-shaped broken ring of imaging light reflecting from a surface of the scanned object;
transforming, in dependence upon a predefined association between each pixel in the image sensor and corresponding points in scanner space, the ridge points to points in scanner space; and
transforming, in dependence upon a relationship between an origin of a coordinate system defining scanner space and an origin of another coordinate system defining object space, the points in scanner space to points in object space.
19 . The method of claim 12 further comprising constructing by the one or more data processors a 3D image of the scanned object based upon the sequence of images and the tracked positions of the scanner, including:
establishing, for each scanned image, transforming tensor values for a transforming tensor that expresses a relationship between a coordinate system defining object space and a coordinate system defining scanner space; and
transforming locations in scanner space of imaging pixels from each scanned image to corresponding scanned points in object space, the transforming carried out with the transforming tensor according to:
[
x
′
y
′
z
′
1
]
≡
[
R
11
R
12
R
13
T
1
R
21
R
22
R
23
T
2
R
31
R
32
R
33
T
3
0
0
0
1
]
[
x
y
z
1
]
,
wherein:
the T values in the tensor express the translation of scanner space with respect to object space,
the R values express the rotation of scanner space with respect to object space, vector x,y,z represents a location of an imaging pixel in scanner space, and vector x′,y′,z′ represents a location of scanned point in object space that corresponds to the location x,y,z in scanner space.
20 . The method of claim 19 wherein the scanned object is an ear, and the object space is taken as ear space.Cited by (0)
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