Method and device for fall prevention and detection
First Claim
1. A method of detecting an object in a bed, said method comprisingcapturing, by an optical sensor, a number of consecutive image frames comprising at least a first and a second image frame;
- determining, by a difference image determinator a difference image by subtracting said first image frame with said second image frame;
determining, by a difference pixel determinator, a number of difference pixels in a bed zone of said difference image and a number of difference pixels outside said bed zone;
calculating, by a share determinator, a share of difference pixels in said bed zone by calculating a ratio between said number of difference pixels in said bed zone and a number of difference pixels outside said bed zone;
determining, by an in-bed determinator, if said object is present in said bed by determining if said share is larger than a reference share; and
transmitting, by a transmitter, a signal indicating that said object is present in said bed if said object is determined to be present in said bed.
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Abstract
Method and device for fall prevention and detection, specifically for the elderly care based on digital image analysis using an intelligent optical sensor. The fall detection is divided into two main steps; finding the person on the floor, and examining the way in which the person ended up on the floor. When the first step indicates that the person is on the floor, data for a time period of a few seconds before and after the indication is analyzed in the second step. If this indicates a fall, a countdown state is initiated in order to reduce the risk of false alarms, before sending an alarm. The fall prevention is also divided into two main steps: identifying a person entering a bed; and identifying the person leaving the bed to end up standing beside it.
38 Citations
23 Claims
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1. A method of detecting an object in a bed, said method comprising
capturing, by an optical sensor, a number of consecutive image frames comprising at least a first and a second image frame; -
determining, by a difference image determinator a difference image by subtracting said first image frame with said second image frame; determining, by a difference pixel determinator, a number of difference pixels in a bed zone of said difference image and a number of difference pixels outside said bed zone; calculating, by a share determinator, a share of difference pixels in said bed zone by calculating a ratio between said number of difference pixels in said bed zone and a number of difference pixels outside said bed zone; determining, by an in-bed determinator, if said object is present in said bed by determining if said share is larger than a reference share; and transmitting, by a transmitter, a signal indicating that said object is present in said bed if said object is determined to be present in said bed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An image capturing device configured to detect an object in a bed, said image capturing device comprising
an optical sensor configured to capture a number of consecutive image frames comprising at least a first and a second image frame, a difference image determinator configured to determine a difference image by subtracting said first image frame with said second image frame, a difference pixel determinator configured to determine a number of difference pixels in a bed zone of said difference image and a number of difference pixels outside said bed zone, a share determinator configured to calculate a share of difference pixels in said bed zone by calculating a ratio between said number of difference pixels in said bed zone and said number of difference pixels outside said bed zone, an in-bed determinator configured to determine if said object is present in said bed by determining if said share is larger than a reference share, and a transmitter configured to transmit a signal indicating that said object is present in said bed if said object is determined to be present in said bed by said in-bed determinator.
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23. A computer readable storage medium, comprising computer program code stored thereon which, when executed on a processor carries out the steps of:
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capturing a number of consecutive image frames comprising at least a first and a second image frame; determining a difference image by subtracting said first image frame with said second image frame; determining a number of difference pixels in a bed zone of said difference image and a number of difference pixels outside said bed zone; calculating a share of difference pixels in said bed zone by calculating a ratio between said number of difference pixels in said bed zone and a number of difference pixels outside said bed zone; determining if said object is present in said bed by determining if said share is larger than a reference share; and transmitting a signal indicating that said object is present in said bed if said object is determined to be present in said bed.
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Specification