Measurement, layout, marking, firestop stick

Patent metadata

Field	Value
Publication number	US-10300573-B2
Application number	US-201715604172-A
Country	US
Kind code	B2
Filing date	May 24, 2017
Priority date	May 24, 2017
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

Multiple cameras are used for tool positioning, as-built documentation, and/or personnel monitoring in construction site. A camera unit comprises one or more imaging devices, a processing computer, and a communication device. The camera units are placed at multiple locations in a construction site to cover an area. The camera units are self-positioned by detecting a calibration target that moves within a working volume. The camera units can detect and calculate positions of objects, including measurement sticks, tools, personnel, etc., in the area.

First claim

What is claimed is:

1. A system for providing position and orientation of an object at a worksite, the system comprising:
a first camera unit;
a second camera unit;
a third camera unit;
a stick, wherein the stick comprises:
central markings of known dimensions;
an end marking of known dimensions;
the end marking has different dimensions than the central markings; and
the central markings have a repeating pattern; and

one or more processors configured to track a position and an orientation of the stick in three dimensions based on known dimensions of the end marking, the repeating pattern of the central markings, and known positions of the first camera unit, the second camera unit, and the third camera unit.

2. The system of claim 1 , further comprising a fourth camera unit.

3. The system of claim 1 , further comprising a chip set for coordinating timing of the first camera unit, the second camera unit, and the third camera unit in acquiring images.

4. The system of claim 1 , wherein
the one or more processors are configured to use the repeating pattern of the central markings to determine a scale of the stick in images to determine a dimension of the end marking in images.

5. The system of claim 1 , wherein the one or more processors are configured to track the position and the orientation of the stick in three dimensions based on the known dimensions of the central markings, known dimensions of the end marking, and known positions of the first camera unit, the second camera unit, and the third camera unit by:
acquiring a plurality of images of the object using the first camera unit, the second camera unit, and the third camera unit, wherein the object has a first end and a second end;
calculating a plurality of two-dimensional line equations based on the plurality of images;
calculating a three-dimensional line equation based on the plurality of two-dimensional line equations;
determining the first end and/or the second end of the object in each of the plurality of images; and
determining coordinates of the object in three dimensions based on determining the first end and/or the second end of the object in the plurality of images.

6. The system of claim 5 , wherein the one or more processors are configured to calculate the plurality of two-dimensional line equations by:
converting color images to gray tone,
applying a derivative filter to gray-tone images,
subtracting background in images,
detecting key points to identify the object in images, and
refining an initial line equation based on detecting the key points.

7. The system of claim 1 , wherein the stick comprises:
a first end,
a second end opposite the first end,
a first marking nearer the first end than the second end for imaging by the first camera unit and the second camera unit, and
a second marking between the first marking and the second end for imaging by the first camera unit and the second camera unit.

8. The system of claim 7 , wherein the stick has a length equal to or greater than 0.5 meters and equal to or less than 1.5 meters.

9. The system of claim 1 , further comprising:
a first set of templates for determining a scale of the repeating pattern and to use for selecting a template of a second set of templates, and
the second set of templates for identifying an end of the stick.

10. The system of claim 9 , wherein each template of the first set of templates has a width, and the width is equal to or greater than one pixel and equal to or less than 20 pixels.

Assignees

• Trimble Inc

Inventors

• Kahle Kent
• Lee Young Jin

Classifications

• G01C15/06

  Surveyors' staffs; Movable markers · CPC title

• G01C15/02

  Means for marking measuring points · CPC title

• G01C15/002

  Active optical surveying means (optical plumbing G01C15/105) · CPC title

• G01C15/00

  Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00 · CPC title

• H04N7/181 Primary

  for receiving images from a plurality of remote sources · CPC title