Human presence detection techniques
View Patent ↗Techniques are disclosed for detecting stationary presence using IR sensor data. A number of IR images may be captured based on IR sensor data and these IR images may be averaged over various time intervals to calculate a number of average IR frames. The difference between these average IR frames provides a delta frame. A mask frame may be calculated as the summation of delta frames over time, and the value of the mask frame may be used to detect a stationary human presence even when no delta value is calculated. Alternatively, the mask frame may be used to calculate a background frame that represents the IR signature of stationary or cyclical objects within the scanned area that are not intended to trigger the presence detection system. A stationary presence may be determined by subtracting the background frame from a current average IR frame.
1. A presence detection system comprising:
an Infrared (IR) sensor configured to scan an area and capture a plurality of IR frames; and
a processor operatively coupled to the IR sensor and configured to:
receive the plurality of IR frames;
calculate a plurality of average IR frames over various time intervals;
calculate a plurality of delta frames by subtracting a previously calculated average IR frame from a current average IR frame;
detect moving human presence in the area based on the plurality of delta frames;
calculate a mask frame by integrating the plurality of delta frames over a predetermined period of time;
compute a digital mask, wherein the digital mask represents the mask frame in a binary format;
determine whether background estimation is desired;
detect stationary human presence in the area based on at least one of a value of the mask frame and a value of the digital mask in response to determining that background estimation is not desired, wherein the mask frame is multiplied by a diminishing factor that clears stationary and cyclical non-human heat sources from the mask frame after a period of time;
calculate a background frame based on the mask frame in response to determining that background estimation is desired, wherein the background frame includes stationary and cyclical non-human heat sources in the area; and
detect stationary human presence in the area based on
subtracting the background frame from a current average IR frame.
2. The system of claim 1 wherein the processor is further configured to provide a digital output based on whether a human presence exists, and wherein the digital output is used to control at least one of an HVAC, lighting, window blinds, surveillance, and/or security system.
3. The system of claim 1 wherein the processor is further configured to track the location of a human presence within the area based on the value of the mask frame.
4. A method of detecting human occupancy comprising:
scanning an area using an IR sensor;
providing a plurality of IR frames based on data captured by the IR sensor;
calculating, by a processor, a plurality of average IR frames over various time intervals;
calculating, by the processor, a plurality of delta frames, wherein each delta frame is the difference between a current average IR frame and a previously calculated average IR frame;
detecting, by the processor, moving human presence in the area based on the plurality of delta frames;
calculating, by the processor, a mask frame, wherein the mask frame is calculated by integrating the delta frames over a predetermined period of time;
computing, by the processor, a digital mask, wherein the digital mask represents the mask frame in a binary format;
determining, by the processor, whether background estimation is desired;
detecting, by the processor, stationary human presence in the area based on at least one of a value of the mask frame and a value of the digital mask in response to determining that background estimation is not desired, wherein the mask frame is multiplied by a diminishing factor that clears stationary and cyclical non-human heat sources from the mask frame after a period of time;
calculating, by the processor, a background frame based on the mask frame in response to determining that background estimation is desired, wherein the background frame includes stationary and cyclical non-human heat sources in the area;
detecting, by the processor, moving human presence in the area based on
subtracting the background frame from a current average IR frame.
5. The method of claim 4 wherein detecting a plurality of IR frames further comprises combining IR sensor data with camera data.
6. The method of claim 4 further comprising tracking, by the processor, the position of a human presence based on the value of the mask frame.
7. The method of claim 4 further comprising estimating, by the processor, the number and location of human presence within a scanned area based on the value of the mask frame.
8. The method of claim 4 further comprising providing, by the processor, a digital output based on whether a stationary presence exists, wherein the digital output is used to control at least one of an HVAC, lighting, window blinds, surveillance, and/or security system.