Distance measuring device for human body features and method thereof

• US 10,402,996 B2
• Filed: 09/15/2017
• Issued: 09/03/2019
• Est. Priority Date: 09/26/2016
• Status: Active Grant

• Current Assignee: ASUSTek Computer, Inc.
• Original Assignee: ASUSTek Computer, Inc.
• Inventors: Kuo, Hao-Yuan, Han, Chia-Hui, Lin, Wei-Po
• Primary Examiner(s): Harvey, David E
• Application Number:
  US15/705,347
• Publication Number:
  US 20180089851A1
• Time in Patent Office: 718 Days
• CPC Class Codes: A61B 3/00 Apparatus for testing the eyes; Instruments for examining the eyes eye inspection using ultrasonic, sonic or infrasonic waves A61B8/10; devices for treatment of the eyes A61F9/00; exercisers for the eyes A61H5/00; optical systems in general G02B
• CPC Class Codes: A61B 3/111 for measuring interpupillary distance
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/1072 measuring distances on the body, e.g. measuring length, height or thickness A61B5/1076 takes precedence
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/30196 Human being; Person
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A distance measuring device for human body features is provided. The device comprises: an image capturing unit configured to capture a plurality of groups of human images of at least one part of human body in a time interval; an image processing unit configured to analyze to recognize a plurality of feature points in each group of the human images to generate three-dimensional coordinates for each feature point; and a processing unit configured to calculate a distance between a first feature point and a second feature point, calculate a deflection angle for each group of the human images, and generate a weight value. The processing unit has a weighted average calculation based on the weight values and the distances to generate a measurement result.

Claims

1. A distance measuring device for human body features, comprising:

an image capturing unit configured to capture a plurality of groups of human images with at least one part of human body in a time interval;

an image processing unit configured to analyze each group of the human images and recognize a plurality of feature points in each group of the human images, the image processing unit generates three-dimensional coordinates for each feature point; and

a processing unit configured to calculate a distance between a first feature point and a second feature point of each group of the human images according to the three-dimensional coordinates of the first feature point and the second feature point in the feature points, calculate a deflection angle for each group of the human images according to the three-dimensional coordinate of each of the feature points, and generate a weight value corresponding to each distance according to the deflection angle, the processing unit is configured to have a weighted average calculation based on the weight values and the distances to generate a measurement result.

2. The distance measuring device for human body features according to claim 1, wherein the processing unit is configured to generate the deflection angle according to the three-dimensional coordinates of each of the feature points and three-dimensional coordinates of a sample feature point corresponding to each of the feature points.

3. The distance measuring device for human body features according to claim 1, wherein the i^th group of the human image in the groups of the human images has the deflection angle θ

_i, and the processing unit generates the weight value w_i corresponding to the deflection angle θ

_i according to an equation as follow;

4. The distance measuring device for human body features according to claim 1, wherein each group of the human images includes a two-dimensional image and a depth image.

5. The distance measuring device for human body features according to claim 4, wherein the image capturing unit includes:

a two-dimensional camera for generating the two-dimensional image, the two-dimensional image includes two-dimensional coordinates for each of the feature points;

an infrared emitter for emitting infrared light toward the at least one part of the human body; and

an infrared light camera for receiving reflected light of the infrared light, the infrared light camera generates the depth image according to the reflected light, and the depth image includes depth information of each of the feature points;

wherein the image processing unit generates the three-dimensional coordinates for each of the feature points by performing mapping and projection conversion based on the two-dimensional coordinates and the depth information.

6. The distance measuring device for human body features according to claim 5, wherein the processing unit obtains an intensity of the reflected light according to the depth information, the processing unit compares the intensity of the reflected light with a preset light intensity range, the processing unit generates a notification message when the intensity of the reflected light is out of the preset light intensity range.

7. The distance measuring device for human body features according to claim 1, wherein the image capturing unit includes two lens for capturing the group of the human images at a same time point in the time interval, the group of the human images to be measured includes a first image and a second image;

the image processing unit calculates a pixel-value difference between the first image and the second image, and generates the three-dimensional coordinates for each of the feature points according to a distance between the two lens, focal distances of the two lens and the pixel-value difference.

8. The distance measuring device for human body features according to claim 1, wherein the deflection angle is a sum of angles between the at least one part of human body of each of the groups of the human images and an X axis, a Y axis and a Z axis respectively, the processing unit compares the deflection angle with a preset angle, and sends a notification message when the deflection angle is greater than the preset angle.

9. A distance measuring method of human body features, comprising:

capturing a plurality of groups of human images with at least one part of human body in a time interval;

analyzing each group of the human images to recognize a plurality of feature points in the group of the human images;

generating three-dimensional coordinates for each feature point;

calculating a distance between a first feature point and a second feature point of each group of the human images according to the three-dimensional coordinates of the first feature point and the second feature point in the feature points;

calculating a deflection angle for each group of the human images according to the three-dimensional coordinates of each of the feature points;

generating a weight value corresponding to each of the distance according to the deflection angle; and

having a weighted average calculation based on the weight values and the distances to generate a measurement result of the distance between the first feature point and the second feature point.

10. The distance measuring method of the human body features according to claim 9, wherein the step of calculating the deflection angle for each group of the human images according to the three-dimensional coordinates of each of the feature points includes generating the deflection angle according to the three-dimensional coordinates of each of the feature points and three-dimensional coordinates of a sample feature point.

11. The distance measuring method of the human body features according to claim 9, wherein the step of generating the weight value includes the weight value w_i corresponding to each distance is generated according to a following equation with the deflection angle θ

_i;

12. The distance measuring method of the human body features according to claim 9, wherein the step of capturing the groups of the human images with the at least one part of the human body in the time interval includes:

obtaining a two-dimensional image of each group of the human images, the two-dimensional image includes two-dimensional coordinates for each of the feature points;

emitting infrared light toward the at least one part of the human body; and

receiving reflected light of the infrared light to generate a depth image according to the reflected light, the depth image includes depth information of each of the feature points;

wherein the step of generating the three-dimensional coordinates for each feature point includes generating the three-dimensional coordinates for each of the feature points by performing mapping and projection conversion based on the two-dimensional coordinates and the depth information.

13. The distance measuring method of the human body features according to claim 12, wherein after the step of capturing the groups of human images with the at least one part of the human body in the time interval, the distance measuring method of the human body features further includes:

comparing an intensity of the reflected light with a preset light intensity range to generate a first comparison result; and

selectively generating a notification message according to the first comparison result.

14. The distance measuring method of the human body features according to claim 9, wherein the step of capturing the groups of human images with at least the part of the human body in the time interval includes capturing a first image and a second image of the group of the human images via two lens, the two lens have same focal distances and a distance therebetween, and the step of generating the three-dimensional coordinates for each feature point includes:

calculating a pixel-value difference between the first image and the second image, and

generating the three-dimensional coordinates for each of the feature points according to the distance, the focal distances and the pixel-value difference.

15. The distance measuring method of the human body features according to claim 9, wherein after the step of calculating the deflection angle for each group of the human images according to the three-dimensional coordinates of each of the feature points, the distance measuring method of the human body features further includes:

comparing the deflection angle with a preset angle to generate a second comparision result; and

selectively generating a notification message according to the second comparision result.