PATIENT VIDEO MONITORING SYSTEMS AND METHODS HAVING DETECTION ALGORITHM RECOVERY FROM CHANGES IN ILLUMINATION

• US 20140204207A1
• Filed: 01/17/2014
• Published: 07/24/2014
• Est. Priority Date: 01/18/2013
• Status: Active Grant

• Current Assignee: Careview Communications Incorporated
• Original Assignee: Careview Communications Incorporated
• Inventors: Clark, Matthew Cameron, del Carpio, Derek
• Granted Patent: US 10,645,346 B2
• Time in Patent Office: Days
• US Class Current: 348/143
• CPC Class Codes: A61B 2505/03 Intensive care
• CPC Class Codes: A61B 2560/0242 adapted to measure environmental factors, e.g. temperature, pollution
• CPC Class Codes: A61B 5/0046 Arrangements of imaging apparatus in a room, e.g. room provided with shielding or for improved access to apparatus
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7465 Arrangements for interactive communication between patient and care services, e.g. by using a telephone network telemetry of measured physiological signal A61B5/0002
• CPC Class Codes: G08B 13/19604 involving reference image or background adaptation with time to compensate for changing conditions, e.g. reference image update on detection of light level change
• CPC Class Codes: G08B 21/0461 integrated or attached to an item closely associated with the person but not worn by the person, e.g. chair, walking stick, bed sensor
• CPC Class Codes: G08B 21/0476 Cameras to detect unsafe condition, e.g. video cameras
• CPC Class Codes: H04N 21/44218 Detecting physical presence or behaviour of the user, e.g. using sensors to detect if the user is leaving the room or changes his face expression during a TV program methods or arrangements for recognising human body or animal bodies or body parts G06V40/10; methods or arrangements for acquiring or recognising human faces, facial parts, facial sketches, facial expressions G06V40/16; methods or arrangements for recognising movements or behaviour G06V40/20; arrangements for identifying users in broadcast systems H04H60/45
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

Various embodiments concern video patient monitoring with detection zones. Various embodiments can comprise a camera, a user interface, and a computing system. The computing system can be configured to perform various steps based on reception of a frame from the camera, including: calculate a background luminance of the frame; monitor for a luminance change of a zone as compared to one or more previous frames, the luminance change indicative of patient motion in the zone; and compare the background luminance to an aggregate background luminance, the aggregate background luminance based on the plurality of frames. If the background luminance changed by more than a predetermined amount, then the aggregate background luminance can be set to the background luminance, luminance information of the previous frames can be disregarded, and motion detection can be disregarded.

Claims

1. A system for monitoring a patient in a patient area having one or more detection zones, the system comprising:

a camera;

a user interface; and

a computing system configured to receive a chronological series of frames from the camera and perform the following steps based on the reception of each frame of the chronological series;

calculate a background luminance of the frame;

calculate an aggregate background luminance based on a respective background luminance for each a plurality of previous frames of the chronological series;

for each of one or more zones, calculate a zone luminance based at least in part on the background luminance and a plurality of luminance values of a plurality of pixels of the zone;

for each of one or more zones, detect patient motion based on a change between the zone luminance and a previous zone luminance of a previous frame exceeding a zone threshold;

compare the background luminance of the frame to an aggregate background luminance;

if the background luminance changed relative to the aggregate background luminance by more than a predetermined amount, disregard luminance information from the plurality of previous frames when performing the detecting patient motion step and the calculating the aggregate background luminance step for subsequent frames of the chronological series; and

if patient motion is detected, generate an alert with the user interface if the background luminance changed relative to the aggregate background luminance by less than the predetermined amount but refrain from generating the alert if the background luminance changed relative to the aggregate background luminance by more than the predetermined amount.

2. The system of claim 1, wherein the computing system is configured to calculate the background luminance of the frame by determining an average pixel luminance based on each pixel of the frame.

3. The system of claim 1, wherein the computing system is configured to calculate the aggregate background luminance by averaging the respective background luminance for each the plurality of previous frames of the chronological series.

4. The system of claim 1, wherein the computing system is configured to detect patient motion in each zone by determining a pixel difference between the aggregate background luminance and a luminance value of each pixel in the zone, and calculating the zone luminance by aggregating the pixel difference of each pixel of the zone.

5. The system of claim 1, wherein:

the previous zone luminance is based on multiple previous frames of the chronological series; and

the computing system is configured to set, for each zone of the frame, the previous zone luminance to the zone luminance of the frame for performing the detecting patient motion step for at least the next frame of the chronological series.

6. The system of claim 1, wherein the computing system is configured to calculate the aggregate background luminance based on the background luminance of the frame and the respective background luminance for each the plurality of previous frames of the chronological series.

7. The system of claim 1, wherein the plurality of previous frames comprise at least three frames of the chronological series that were received immediately previous to the frame.

8. A system for monitoring a patient in a patient area having one or more detection zones, the system comprising:

a computing system configured to receive a chronological series of frames and perform the following steps based on the reception of each frame of the chronological series;

calculate a background luminance of the frame;

for each zone of one or more zones of the frame, monitor for a luminance change of the zone as compared to one or more frames of a plurality of frames that were previously received from the camera, the luminance change indicative of patient motion in the zone;

compare the background luminance of the frame to an aggregate background luminance, the aggregate background luminance based on the plurality of frames; and

if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than a predetermined amount, set the aggregate background luminance to the background luminance of the frame and dampen luminance of the plurality of frames in subsequent monitoring for the luminance change in the one or more zones.

9. The system of claim 8, wherein the computing system is configured to calculate the background luminance of the frame based on a luminance value from each pixel of the frame.

10. The system of claim 8, wherein the computing system is configured to calculate the background luminance of the frame by determining an average pixel luminance based on each pixel of the frame.

11. The system of claim 8, wherein the computing system is configured to calculate the aggregate background luminance by averaging the background luminance from each of the plurality of frames.

12. The system of claim 8, wherein the computing system is configured to compare the background luminance to the aggregate background luminance by determining a difference between the background luminance of the frame and the aggregate background luminance and determining whether the difference exceeds the predetermined amount, the predetermined amount comprising a background threshold.

13. The system of claim 12, wherein the background threshold discriminates between minor changes in illumination unlikely to cause erroneous movement detection and larger changes in illumination likely to trigger erroneous movement detection.

14. The system of claim 8, wherein the computing system is configured to dampen the luminance information of the plurality of frames by applying a scalar to the luminance information.

15. The system of claim 8, wherein the computing system is configured to dampen the luminance information of the plurality of frames by erasing luminance information from the plurality of frames from memory of the computing system.

16. The system of claim 8, wherein the computing system is configured to generate an alert if the monitoring step identifies the luminance change in the one or more zones of the frame.

17. The system of claim 16, wherein the computing system is configured to suspend or cancel the alert if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than the predetermined amount.

18. The system of claim 8, wherein the computing system is configured to monitor for the luminance change in each zone by determining a pixel difference between the aggregate background luminance and a luminance value of each pixel in the zone, calculating an zone luminance by aggregating the pixel difference of each pixel of the zone, and calculating the luminance change of the zone based on the zone luminance and a historical luminance of the zone, the historical luminance based on the plurality of frames that were previously received from the camera.

19. The system of claim 18, wherein the computing system is configured to set, for each zone of the frame, the historical luminance to the zone luminance if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than the predetermined amount.

20. A method for processing a chronological series of frames generated by a camera to monitor a patient in a patient area having one or more detection zones by performing the following steps based on the generation of each frame in the chronological series, each step performed at least in part by a computing system:

calculating a background luminance of the frame;

for each zone of one or more zones of the frame, monitoring for a luminance change of the zone as compared to one or more frames of a plurality of frames that were previously received from the camera, the luminance change indicative of patient motion in the zone;

comparing the background luminance of the frame to an aggregate background luminance, the aggregate background luminance based on the plurality of frames; and

if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than a threshold amount, setting the aggregate background luminance to the background luminance of the frame and disregarding luminance of the plurality of frames in subsequent monitoring for the luminance change in the one or more zones.

21. The method of claim 20, wherein the background luminance of the frame is calculated based on a luminance value from each pixel of the frame.

22. The method of claim 20, wherein the background luminance of the frame is calculated by determining an average pixel luminance based on each pixel of the frame.

23. The method of claim 20, further comprising calculating the aggregate background luminance by averaging the background luminance from each of the plurality of frames.

24. The method of claim 20, wherein the plurality of frames comprises at least three frames.

25. The method of claim 20, wherein comparing the background luminance to the aggregate background luminance comprises determining a difference between the background luminance of the frame and the aggregate background luminance and determining whether the difference exceeds the predetermined amount, the predetermined amount comprising a background threshold.

26. The method of claim 25, wherein the background threshold discriminates between minor changes in illumination unlikely to cause erroneous movement detection and larger changes in illumination likely to trigger erroneous movement detection.

27. The method of claim 20, wherein disregarding the plurality of frames comprises erasing luminance information from the plurality of frames from a memory component.

28. The method of claim 20, further comprising generating an alert with a user interface if the monitoring step identifies the luminance change in the one or more zones of the frame.

29. The method of claim 28, further comprising suspending or canceling the alert if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than the predetermined amount.

30. The method of claim 20, wherein monitoring for the luminance change in each zone comprises determining a pixel difference between the aggregate background luminance and a luminance value of each pixel in the zone, calculating an zone luminance by aggregating the pixel difference of each pixel of the zone, and calculating the luminance change of the zone based on the zone luminance and a historical luminance of the zone, the historical luminance based on the plurality of frames that were previously received from the camera.

31. The method of claim 30, further comprising setting, for each zone of the frame, the historical luminance to the zone luminance if the comparison determines that the background luminance changed relative to the aggregate background luminance by more than the predetermined amount.