Device, System and Method for Skin Detection

• US 20160171684A1
• Filed: 12/02/2015
• Published: 06/16/2016
• Est. Priority Date: 12/15/2014
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: DE HAAN, Gerard
• Granted Patent: US 9,842,392 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4887 Locating particular structures in or on the body
• CPC Class Codes: G06F 18/23 Clustering techniques
• CPC Class Codes: G06F 18/2323 based on graph theory, e.g. minimum spanning trees [MST] or graph cuts
• CPC Class Codes: G06F 2218/00 Aspects of pattern recognition specially adapted for signal processing
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/13 Edge detection
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06V 10/431 Frequency domain transformation; Autocorrelation
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: G06V 10/7635 based on graphs, e.g. graph cuts or spectral clustering
• CPC Class Codes: G06V 40/15 Biometric patterns based on physiological signals, e.g. heartbeat, blood flow

Abstract

The present invention relates to a device, system and method for skin detection. To enable a reliable, accurate and fast skin detection the proposed device comprises an input unit (20) for obtaining a sequence of image frames acquired over time, a segmentation unit (22) for segmenting an image frame of said sequence of image frames, a tracking unit (24) for tracking segments of the segmented image frame over time in said sequence of image frames, and a clustering unit (26) for clustering the tracked segments to obtain clusters representing skin of a subject by use of one or more image features of said tracked segments.

Claims

1. Device for skin detection comprising:

an input unit for obtaining a sequence of image frames acquired over time,

a segmentation unit for segmenting an image frame of said sequence of image frames,

a tracking unit for tracking segments of the segmented image frame over time in said sequence of image frames,

a clustering unit for clustering the tracked segments to obtain clusters representing skin of a subject by use of one or more image features of said tracked segments.

2. Device as claimed in claim 1,

wherein said segmentation unit is configured to over-segment the image frame that is used for segmentation.

3. Device as claimed in claim 1,

wherein said clustering unit is configured to use temporal color variations of the tracked segments as feature for clustering the tracked segments.

4. Device as claimed in claim 3,

wherein said clustering unit is configured to perform a Fourier transformation of the spatially combined color value of at least part of the pixels in a tracked segment and to cluster two tracked segments into a single cluster if their amplitude peak frequency has substantially the same value and phase.

5. Device as claimed in claim 1,

wherein said clustering unit is configured to compute the inner product between normalized time signals of different tracked segments and to cluster said tracked segments into a single cluster if said inner product exceeds a predetermined threshold.

6. Device as claimed in claim 1,

wherein said clustering unit is configured to use the hue of pixels of the tracked segments as feature for clustering the tracked segments.

7. Device as claimed in claim 1,

wherein said segmentation unit, tracking unit and clustering unit are configured to repeatedly perform segmentation, tracking and clustering, wherein the sequence of acquired image frames used for subsequent repetitions overlap in time.

8. Device as claimed in claim 1,

wherein said segmentation unit is configured to perform a feature point detection, in particular a Harris corner detection.

9. Device as claimed in claim 1,

wherein said segmentation unit is configured to perform a triangulation, in particular a Delaunay triangulation.

10. Device as claimed in claim 2,

wherein said segmentation unit is configured to over-segment the image frame that is used for segmentation based on color, position and/or texture properties.

11. Device as claimed in claim 1,

wherein said tracking unit is configured to track the segments of the segmented image frame using motion estimation.

12. Device as claimed in claim 1,

further comprising a vital signs detector for detecting vital signs of a subject based on image information from detected skin areas within said sequence of image frames.

13. System for skin detection comprising:

an imaging unit for acquiring a sequence of image frames over time and

a device for skin detection as claimed in claim 1 based on the acquired sequence of image frames.

14. Method for skin detection comprising:

obtaining a sequence of image frames acquired over time,

segmenting an image frame of said sequence of image frames,

tracking segments of the segmented image frame over time in said sequence of image frames,

clustering the tracked segments to obtain clusters representing skin of a subject by use of one or more image features of said tracked segments.

15. Computer program comprising program code means for causing a computer to carry out the steps of the method as claimed in claim 14 when said computer program is carried out on the computer.