1. An apparatus for automatically measuring a volume of urine in a bladder using ultrasound signals, comprising:
a transducer for transmitting the ultrasound signals and receiving the ultrasound signals returning from the bladder and surrounding tissues;
a central control unit configured to generate a plurality of ultrasound scan planes using the received ultrasound signals of the transducer, each of the ultrasound scan planes is separated by a selected angle and consists of a plurality of scan lines, to produce a scan cone for scanning the bladder;
detect distances between front and back walls of the bladder for each scan line in the ultrasound scan planes;
automatically determine an area of the bladder using the detected distances of the scan lines for each ultrasound scan plane;
automatically generate a virtual radius of the bladder using a determined area of the bladder for each ultrasound scan plane;
automatically determine a calibration coefficient for each ultrasound scan plane using the detected distances of the scan lines;
automatically calibrate the virtual radius of the bladder for each ultrasound scan plane using the calibration coefficient; and
automatically determine the volume of urine in the bladder by calculating a volume of a sphere of which the radius is an average of the calibrated virtual radii for the ultrasound scan planes,
wherein the central control unit is configured to determine the virtual radius of the bladder for each ultrasound scan plane by using the radius of a circle of which the area is the same as the detected area of the bladder for the corresponding ultrasound scan plane, and
wherein the central control unit is configured to calculate the calibration coefficient for each ultrasound scan plane using the following equation:
ComFactor
\u2061
i
=
MaxBladderDepth
BladderDepth
\u2061
i
where ComFactori is a calibration coefficient for an i-th ultrasound scan plane, BladderDepthi is a bladder depth for the i-th ultrasound scan plane and is determined by a maximum of distances between front wall and back wall of bladder in scan lines for the i-th ultrasound scan plane, MaxBladderDepth is determined by a maximum of the bladder depths for the ultrasound scan planes.
2. The apparatus of claim 1, wherein the virtual radius is calibrated using the following equation:
ComRi=ComFactori\xd7ri
where, \u2018ComRi\u2019 is a calibrated virtual radius of the bladder for i-th ultrasound scan plane, \u2018ComFactori\u2019 is a calibration coefficient for an i-th ultrasound scan plane, and \u2018ri\u2019 is a virtual radius of the bladder for i-th ultrasound scan plane.
3. A method for automatically measuring a volume of urine in a bladder using ultrasound signals, comprising the steps of:
transmitting ultrasound signals and receiving the ultrasound signals returning from the bladder and surrounding tissues;
generating a plurality of ultrasound scan planes using the received ultrasound signals, each of the ultrasound scan planes is separated by a selected angle and consists of a plurality of scan lines, to produce a scan cone for scanning the bladder;
detecting distances between front and back walls of the bladder for each scan line in the ultrasound scan planes;
determining an area of the bladder using the detected distances of the scan lines for each ultrasound scan plane;
generating a virtual radius of the bladder using a determined area of the bladder for each ultrasound scan plane;
determining a calibration coefficient for each ultrasound scan plane using the detected distances of the scan lines;
calibrating the virtual radius of the bladder for each ultrasound scan plane using the calibration coefficient;
determining the volume of urine in the bladder by calculating a volume of a sphere of which the radius is an average of the calibrated virtual radii for the ultrasound scan planes,
wherein the virtual radius of the bladder for each ultrasound scan plane is determined by the radius of a circle of which the area is the same as the area of the bladder for the corresponding ultrasound scan plane, and
wherein the calibration coefficient for each ultrasound scan plane is calculated using the following equation:
ComFactor
\u2061
i
=
MaxBladderDepth
BladderDepth
\u2061
i
where ComFactori is a calibration coefficient for an i-th ultrasound scan plane, BladderDepthi is a bladder depth for the i-th ultrasound scan plane and is determined by a maximum of the distances between FW (front wall) and BW (back wall) of the bladder in the scan lines for the i-th ultrasound scan plane, MaxBladderDepth is determined by the maximum of the bladder depths in the ultrasound scan planes.
4. The method of claim 3, wherein the virtual radius is calibrated using the following equation:
ComRi=ComFactori\xd7ri
where, \u2018ComRi\u2019 is a calibrated virtual radius of the bladder for i-th ultrasound scan plane, \u2018ComFactori\u2019 is a calibration coefficient for an i-th ultrasound scan plane, and \u2018ri\u2019 is a virtual radius of the bladder for i-th ultrasound scan plane.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An information processing apparatus comprising:
a storage unit configured to store a model representing a shape of a target object;
an approximate position and orientation acquisition unit configured to acquire an approximate position and orientation of the target object;
an acquisition unit configured to acquire a two-dimensional image of the target object and information about a three-dimensional point group on a surface of the target object;
a detection unit configured to detect an image feature from the acquired two-dimensional image;
an association unit configured to associate, based on the approximate position and orientation, the detected image feature with a geometric feature included in the model and to associate a distance point of the three-dimensional point group with the geometric feature included in the model;
a first registration error acquisition unit configured to convert the image feature on the two-dimensional image into a three-dimensional space and acquire a first registration error between the converted image feature and the geometric feature of the model;
a second registration error acquisition unit configured to acquire a second registration error between the associated distance point and the geometric feature of the model; and
a position and orientation derivation unit configured to derive a position and orientation of the target object based on the acquired first registration error and the acquired second registration error.
2. The information processing apparatus according to claim 1, wherein based on a viewpoint position of an image capturing unit having captured the two-dimensional image, the first registration error acquisition unit back-projects the image feature on the two-dimensional image to the three-dimensional space and acquires the first registration error between the back-projected image feature and the geometric feature of the model.
3. The information processing apparatus according to claim 1, wherein the image feature is converted into the three-dimensional space based on a straight line passing through a viewpoint position of an image capturing unit having captured the two-dimensional image and a position of the image feature on the two-dimensional image.
4. The information processing apparatus according to claim 1, wherein the first registration error acquisition unit acquires as the first registration error a distance between a straight line that passes through a viewpoint position of an image capturing unit and a position of the image feature on the two-dimensional image and a straight line that passes through the geometric feature of the model disposed at the approximate position and orientation in the three-dimensional space and is parallel to a three-dimensional direction of the geometric feature of the model.
5. The information processing apparatus according to claim 1, wherein the first registration error acquisition unit acquires as the first registration error a distance between a plane that includes a straight line passing through a viewpoint position of an image capturing unit and a position of the image feature and is along a direction of the image feature and a position of the geometric feature of the model disposed at the approximate position and orientation in the three-dimensional space.
6. The information processing apparatus according to claim 1, wherein the first registration error acquisition unit back-projects the image feature to the three-dimensional space using a straight line connecting a viewpoint position of an image capturing unit and a position of the image feature and a depth value of the approximate position and orientation, and acquires as the first registration error a distance between a position of the back-projected image feature and a plane that includes a straight line passing through the viewpoint position and the geometric feature of the model disposed in the approximate position and orientation and is along a direction of the geometric feature of the model.
7. The information processing apparatus according to claim 1, wherein the second registration error acquisition unit acquires as the second registration error a distance between a local surface feature of the model and the distance point.
8. The information processing apparatus according to claim 7, wherein based on the approximate position and orientation, the association unit projects the model to a range image and searches for a distance point corresponding to a geometric feature of the projected model so that the geometric feature of the projected model is associated with the distance point corresponding to the model.
9. The information processing apparatus according to claim 1, wherein based on the approximate position and orientation, the association unit projects the model to the two-dimensional image and searches for an image feature corresponding to a geometric feature of the projected model so that the geometric feature of the projected model is associated with the image feature corresponding to the model.
10. The information processing apparatus according to claim 1, wherein the information about the three-dimensional point group is acquired from a range image obtained by capturing an image of the target object.
11. The information processing apparatus according to claim 1, wherein the position and orientation derivation unit derives the position and orientation of the target object by updating the approximate position and orientation to minimize the acquired first registration error and the acquired second registration error.
12. The information processing apparatus according to claim 1, wherein the model is a computer-aided design (CAD) model.
13. The information processing apparatus according to claim 1, wherein the approximate position and orientation is acquired by performing pattern matching on the two-dimensional image or the information about the three-dimensional point group.
14. The information processing apparatus according to claim 1, wherein the image feature is an edge.
15. The information processing apparatus according to claim 1, further comprising:
an image capturing unit configured to capture a two-dimensional image and a range image of the target object,
wherein the information about the three-dimensional point group is acquired from the range image.
16. The information processing apparatus according to claim 1, further comprising an operation unit configured to operate the target object based on a result of estimation of the position and orientation of the target object by the position and orientation derivation unit.
17. An information processing method comprising:
acquiring an approximate position and orientation of a target object;
acquiring a two-dimensional image of the target object and information about a three-dimensional point group on a surface of the target object;
detecting an image feature from the acquired two-dimensional image;
associating, based on the approximate position and orientation, the detected image features with a geometric feature included in a model that is stored in a storage unit and represents a shape of the target object, and associating a distance point of the three-dimensional point group with the geometric feature included in the model;
converting the image feature on the two-dimensional image into a three-dimensional space and acquiring a first registration error between the converted image feature and the geometric feature of the model;
acquiring a second registration error between the associated distance point and the geometric feature of the model; and
deriving a position and orientation of the target object based on the acquired first registration error and the acquired second registration error.
18. A storage medium storing a computer program for causing a computer to function as each unit of an information processing apparatus comprising:
a storage unit configured to store a model representing a shape of a target object;
an approximate position and orientation acquisition unit configured to acquire an approximate position and orientation of the target object;
an acquisition unit configured to acquire a two-dimensional image of the target object and information about a three-dimensional point group on a surface of the target object;
a detection unit configured to detect an image feature from the acquired two-dimensional image;
an association unit configured to associate, based on the approximate position and orientation, the detected image feature with a geometric feature included in the model and to associate a distance point of the three-dimensional point group with the geometric feature included in the model;
a first registration error acquisition unit configured to convert the image feature on the two-dimensional image into a three-dimensional space and acquire a first registration error between the converted image feature and the geometric feature of the model;
a second registration error acquisition unit configured to acquire a second registration error between the associated distance point and the geometric feature of the model; and
a position and orientation derivation unit configured to derive a position and orientation of the target object based on the acquired first registration error and the acquired second registration error.