# US 10,319,104 B2 · Method and system for determining datum plane

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- Number: US 10,319,104 B2
- Document ID: US10319104B2
- Status: Granted
- Kind: B2
- Application number: 15/525,703
- Filed: 2016-06-08
- Published: 2018-03-15
- Granted: 2019-06-11
- Earliest claimed: 2016-03-09
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Jibo Zhao; Yingjie Li
- Web page: https://patentgrep.com/patent/US10319104B2

## CPC

- G06T 7/564: from contours
- G06T 7/12: Edge-based segmentation
- G06T 7/13: Edge detection
- G06T 7/162: involving graph-based methods
- G06T 7/60: Analysis of geometric attributes
- G06T 2207/10028: Range image; Depth image; 3D point clouds
- G06T 2207/20072: Graph-based image processing
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A method and a system for determining a datum plane are disclosed. The method for determining a datum plane includes: acquiring a depth image; performing edge extraction on the depth image to form an edge image, the edge image including a plurality of planar graphs; and selecting from the planar graphs in the edge image to determine the datum plane. The technical solutions provided by the disclosure can easily match the virtual object with the real scene in real time, and improve users' sensory experience beyond reality.

## Claims

### Claim 1

A method for determining a datum plane, comprising:
acquiring a depth image;
performing edge extraction on the depth image to form an edge image, the edge image comprising a plurality of planar graphs; and
selecting from the planar graphs in the edge image to determine the datum plane,
wherein the step of performing edge extraction on the depth image to form an edge image comprises:
obtaining a gradient change rate of the depth image according to a preset gradient algorithm;
forming a binary image according to the gradient change rate; and
performing edge extraction on the binary image to form the edge image.

### Claim 2 (depends on 1)

The method for determining a datum plane according to claim 1, further comprising, after the step of selecting from the planar graphs in the edge image to determine the datum plane, a step of:
forming a datum coordinate system based on the datum plane.

### Claim 3 (depends on 1)

The method for determining a datum plane according to claim 1, wherein the step of selecting from the planar graphs in the edge image to determine the datum plane comprises:
selecting planar graphs each having an image depth value decreasing gradually from bottom to top to form a first planar graph collection; and
selecting from the planar graphs in the first planar graph collection to determine the datum plane.

### Claim 4 (depends on 3)

The method for determining a datum plane according to claim 3, wherein the step of selecting from the planar graphs in the first planar graph collection to determine the datum plane comprises:
selecting planar graphs each having an area larger than 15% of an area of the edge image to form a second planar graph collection; and
selecting from the planar graphs in the second planar graph collection to determine the datum plane.

### Claim 5 (depends on 4)

The method for determining a datum plane according to claim 4, wherein the step of selecting from the planar graphs in the second planar graph collection to determine the datum plane comprises:
selecting, from the second planar graph collection, a planar graph whose center point is closest to the bottom of the edge image to be the datum plane.

### Claim 6 (depends on 2)

The method for determining a datum plane according to claim 2, wherein the datum coordinate system comprises a first axis, a second axis and a third axis perpendicular to one another, and the step of forming a datum coordinate system based on the datum plane comprises:
obtaining coordinates of at least three points in the datum plane; and
forming the datum coordinate system based on the coordinates of the at least three points such that the first axis is perpendicular to the datum plane, and the second axis and the third axis are in the datum plane.

### Claim 7 (depends on 6)

The method for determining a datum plane according to claim 6, wherein the step of obtaining coordinates of at least three points in the datum plane comprises:
obtaining a maximum square in the datum plane; and
obtaining coordinates of four vertices of the maximum square.

### Claim 8 (depends on 2)

The method for determining a datum plane according to claim 2, further comprising, before the step of forming a datum coordinate system based on the datum plane, a step of:
selecting from the planar graphs in the edge image to determine a reference plane, the reference plane being parallel to the datum plane; and
wherein the step of forming a datum coordinate system based on the datum plane comprises:
forming the datum coordinate system based on the datum plane and the reference plane such that an origin of the datum coordinate system is in the reference plane.