Light point identification method

• US 10,456,214 B2
• Filed: 01/28/2015
• Issued: 10/29/2019
• Est. Priority Date: 01/28/2015
• Status: Active Grant

• Current Assignee: Brainlab AG
• Original Assignee: Brainlab AG
• Inventors: Manus, Johannes
• Primary Examiner(s): Baker, Charlotte M
• Application Number:
  US15/543,053
• Publication Number:
  US 20180008371A1
• Time in Patent Office: 1,735 Days
• Field of Search: 382128, 600407, 600424, 600431, 378 65, 606 4, 348 77
• 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, 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-define emission pattern of light pulses; and

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

2. The method of claim 1, 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.

3. The method of claim 1, 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.

4. The method of claim 1, 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.

5. The method of claim 1, 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.

6. The method of claim 1, 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.

7. The method of claim 1, 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.

8. The method of claim 1, further comprising generating a light mark on a surface via a light beam.

9. The method of claim 8, further comprising determining three-dimensional spatial positions of the reflected light pulse corresponding to the light mark generated on the surface.

10. The method of claim 9, further comprising registering a shape of the surface based on positional data of the reflected light pulse.