LIGHT POINT IDENTIFICATION METHOD

• US 20180008371A1
• Filed: 01/28/2015
• Published: 01/11/2018
• Est. Priority Date: 01/28/2015
• Status: Active Grant

• Current Assignee: Brainlab AG
• Original Assignee: Brainlab AG
• Inventors: Manus, Johannes
• Granted Patent: US 10,456,214 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2057 Details of tracking cameras
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 2090/371 with simultaneous use of two cameras
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61B 90/361 Image-producing devices, e.g. surgical cameras
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A data processing method performed by a computer for detecting reflections of light pulses, comprising the steps: acquiring a camera signal representing a series of camera images of a camera viewing field; detecting whether the camera signal includes one or more light mark portions within the camera viewing field possibly representing a light pulse reflection; relating the detected light mark portions in the series of camera images to a pre-defined emission pattern of the light pulses; and determining that a light mark portion is a reflected light pulse, if the light mark portion in the series of camera images matches to the pre-defined emission pattern of the light pulses.

Claims

1. A method for detecting reflections of light pulses, comprising the steps:

acquiring, from a camera system, a series of camera images of a camera viewing field;

detecting whether the series of camera images include one or more light mark portions within the camera viewing field, wherein the one or more light mark portions detected represent possible light pulse reflections;

comparing the one or more light mark portions detected in the series of camera images to a pre-defined emission pattern of the light pulses; and

determining that a light mark portion is a reflected light pulse, when the light mark portion detected in the series of camera images matches the pre-defined emission pattern of the light pulses.

2. The method of claim 1, wherein the series of camera images of the camera viewing field is at least one of a series of subsequent camera images taken with a pre-defined time interval between two camera images or a series of stereoscopic camera images, or includes 3D data.

3. The method of claim 1, wherein the pre-defined emission pattern of the light pulses includes a light pulse during every n-th camera image, wherein n is greater than or equal to 2.

4. The method of claim 1, further comprising determining a match of the light mark portion in the series of camera images to the pre-defined emission pattern of the light pulses when the light mark portion is only detected in camera images corresponding to emissions in the pre-defined emission pattern of the light pulses and is not detected in camera images corresponding to periods of no emission in the pre-defined emission pattern of the light pulses.

5. The method of claim 1, further comprising determining a light mark portion in the series of camera images to be a reflected light pulse when the light mark portion is detected m times in n consecutive camera images, wherein n is greater than or equal to 3 and m is less than n.

6. The method of claim 1, further comprising determining a light mark portion in the series of camera images to be a reflected light pulse when two subsequently detected light mark portions are determined to not exceed a pre-defined maximum distance.

7. The method of claim 1, further comprising determining a light mark portion in the series of camera images to be a reflected light pulse when a single reflected light pulse is identified in a camera image.

9. A computer-readable storage medium having stored thereon a computer-executable instruction for a program which, when running on a computer, causes the computer to perform the method of claim 1.

10. A system comprising a computer having the computer-readable storage medium of claim 9 and which executes the computer-executable instruction of the program stored thereon.

8. A method for determining or registering to a shape of a surface using a medical navigation system comprising the following steps:

generating light marks (3) on the surface by means of a light beam (2);

acquiring, from a camera system, a series of camera images of a camera viewing field;

detecting whether the series of camera images include one or more light mark portions within the camera viewing field, wherein the one or more light mark portions detected represent possible light pulse reflections;

comparing the one or more light mark portions detected in the series of camera images to a pre-defined emission pattern of the light pulses;

determining that a light mark portion is a reflected light pulse, when the light mark portion detected in the series of camera images matches the pre-defined emission pattern of the light pulses;

determining three-dimensional, spatial positions of the light pulse reflections using the navigation system; and

determining or registering to the shape of the surface by means of the positional data of the light pulse reflections.

11-15. -15. (canceled)

16. A method, comprising:

acquiring, from a camera system, a series of camera images of a camera viewing field;

detecting whether the series of camera images include a light mark within the camera viewing field, wherein the light mark detected represents a possible light pulse reflection;

comparing a time pattern of the light mark detected in the series of camera images to a pre-defined emission pattern of light pulses; and

determining that the light mark detected is a reflected light pulse when the time pattern the light mark detected in the series of camera images matches the pre-defined emission pattern.

17. The method of claim 16, wherein the series of camera images of the camera viewing field is a series of subsequent camera images taken with a pre-defined time interval between two camera images a series of stereoscopic camera images, or includes 3D data.

18. The method of claim 16, wherein the pre-defined emission pattern of light pulses includes a light pulse during every n-th camera image, wherein n is greater than or equal to 2.

19. The method of claim 16, further comprising determining a match of the time pattern of the light mark detected in the series of camera images to the pre-defined emission pattern of light pulses when the light mark is only detected in camera images that align with emissions in the pre-defined emission pattern of light pulses and the light mark is not detected in camera images corresponding to periods of no emission in the pre-defined emission pattern of light pulses.

20. The method of claim 16, further comprising determining the light mark detected in the series of camera images to be a reflected light pulse when the time pattern of the light mark detected indicates m detections in n consecutive camera images, wherein n is greater than or equal to 3 and m is less than n.

21. The method of claim 16, further comprising determining the light mark detected in the series of camera images to be a reflected light pulse when the time pattern of the light mark includes two subsequent detection within a pre-defined maximum distance.

22. The method of claim 16, determining the light mark detected in the series of camera images to be a reflected light pulse when a single reflected light pulse is identified in a camera image.

23. The method of claim 16, further comprising generating a light mark on a surface via a light beam.

24. The method of claim 23, further comprising determining three-dimensional spatial positions of the reflected light pulse corresponding to the light mark generated on the surface.

25. The method of claim 24, further comprising registering a shape of the surface based on positional data of the reflected light pulse.