Processing a video for tidal chest volume estimation
First Claim
1. A method for determining chest volume from video captured of a subject of interest being monitored for respiratory function, the method comprising:
- manipulating, in order to reduce image artifacts, at least one structured illumination source and at least one unstructured illumination source illuminating a scene being captured by a video system actively acquiring a video of a target region containing at least a partial view of a thoracic region of a subject of interest being monitored for respiratory function, captured images corresponding to at least an inspiration and expiration cycle of said subject, wherein said manipulating includes spectrally multiplexing said at least one structured illumination source and at least one unstructured illumination source by making a wavelength range of said at least one structured illumination source narrower than a wavelength range of said at least one unstructured illumination source such that reflected energy from both illumination sources can be recovered via filtering, said at least one structured illumination source and at least one unstructured illumination source having significantly overlapping spectral bands;
for each of said captured images, comparing spatial characteristics of said reflection in said captured images to known spatial characteristics of undistorted projected patterns such that a spatial distortion of captured patterns can be characterized, said spatial distortion having been introduced by a reflection of said captured patterns off a surface of said target region;
calculating a sequence of depth maps from said spatial distortion, in depth map being characterized for each of said captured images;
for each depth map in said sequence of depth maps;
determining spatial coordinates corresponding to said depth map; and
estimating a 3D chest volume for each depth map in said sequence of depth maps;
calculating said subject'"'"'s chest volume using a proportionality constant which converts estimated 3D volumes to an approximation of a measured chest volume as measured by laboratory tests; and
storing, using a processor, said subject'"'"'s chest volume to a storage device.
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Abstract
What is disclosed is a system and method for estimating tidal chest volume using 3D surface reconstruction based on an analysis of captured reflections of structured illumination patterns from the subject with a video camera. The imaging system hereof captures the reflection of the light patterns from a target area of the subject'"'"'s thoracic region. The captured information produces a depth map and a volume is estimated from the resulting 3D map. The teachings hereof provide a non-contact approach to patient respiration monitoring that is particularly useful for infant care in a neo-natal intensive care unit (NICU), and can aid in the early detection of sudden deterioration of physiological condition due to detectable changes in respiratory function. The systems and methods disclosed herein provide an effective tool for tidal chest volume study and respiratory function analysis.
45 Citations
19 Claims
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1. A method for determining chest volume from video captured of a subject of interest being monitored for respiratory function, the method comprising:
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manipulating, in order to reduce image artifacts, at least one structured illumination source and at least one unstructured illumination source illuminating a scene being captured by a video system actively acquiring a video of a target region containing at least a partial view of a thoracic region of a subject of interest being monitored for respiratory function, captured images corresponding to at least an inspiration and expiration cycle of said subject, wherein said manipulating includes spectrally multiplexing said at least one structured illumination source and at least one unstructured illumination source by making a wavelength range of said at least one structured illumination source narrower than a wavelength range of said at least one unstructured illumination source such that reflected energy from both illumination sources can be recovered via filtering, said at least one structured illumination source and at least one unstructured illumination source having significantly overlapping spectral bands; for each of said captured images, comparing spatial characteristics of said reflection in said captured images to known spatial characteristics of undistorted projected patterns such that a spatial distortion of captured patterns can be characterized, said spatial distortion having been introduced by a reflection of said captured patterns off a surface of said target region; calculating a sequence of depth maps from said spatial distortion, in depth map being characterized for each of said captured images; for each depth map in said sequence of depth maps; determining spatial coordinates corresponding to said depth map; and estimating a 3D chest volume for each depth map in said sequence of depth maps; calculating said subject'"'"'s chest volume using a proportionality constant which converts estimated 3D volumes to an approximation of a measured chest volume as measured by laboratory tests; and storing, using a processor, said subject'"'"'s chest volume to a storage device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system to determine chest volume from video captured of a subject of interest being monitored for respiratory function, the system comprising:
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a video camera and an illuminator configured to project a pattern of structured illumination, said video camera being, at least in part, sensitive to electromagnetic radiation in a wavelength range contains the wavelength of said structured illumination to capture time-varying video of a subject of interest being monitored for respiratory function; and a processor in communication with a memory, said processor executing machine readable instructions to perform; receive a video captured by said video camera of a target region containing at least a partial view of a thoracic region of said subject, each captured image comprising sampled radiation emitted by a reflection of a patterned structured illumination off said target region, said captured images corresponding to at least an inspiration and expiration cycle of said subject; manipulate, in order to reduce image artifacts, at least one structured illumination source and at least one unstructured illumination source illuminating a scene being captured by a video system actively acquiring a video of a target region containing at least a partial view of a thoracic region of a subject, said captured images corresponding to at least an inspiration and expiration cycle of said subject, wherein said manipulating includes spectrally multiplexing said at least one structured illumination source and at least one unstructured illumination source by making a wavelength range of said at least one structured illumination source narrower than a wavelength range of said at least one unstructured illumination source such that reflected energy from both illumination sources can be recovered via filtering, said at least one structured illumination source and at least one unstructured illumination source having significantly overlapping spectral bands; compare spatial characteristics of said reflection in said captured images to known spatial characteristics of undistorted projected patterns such that a spatial distortion of captured patterns can be characterized, said spatial distortion having been introduced by a reflection of said captured patterns off a surface of said target region; calculate a sequence of depth maps from said spatial distortion, in depth map being characterized for each of said captured images; for each depth map in said sequence of depth maps; determine spatial coordinates corresponding to said depth map; and estimate a 3D chest volume for each depth map in said sequence of depth maps; calculate said subject'"'"'s chest volume using a proportionality constant which converts estimated 3D volumes to an approximation of a measured chest volume as measured by laboratory tests; and store said subject'"'"'s chest volume to a storage device. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A computer implemented method for determining chest volume from video captured of a subject of interest being monitored for respiratory function, the method comprising:
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manipulating, in order to reduce image artifacts, at least one structured illumination source and at least one unstructured illumination source illuminating a scene being captured by a video system actively acquiring a video of a target region containing at least a partial view of a thoracic region of a subject of interest being monitored for respiratory function, captured images corresponding to at least an inspiration and expiration cycle of said subject, wherein said manipulating includes spectrally multiplexing said illumination sources said at least one structured illumination source and at least one unstructured illumination source by making a wavelength range of said at least one structured illumination source narrower than a wavelength range of said at least one unstructured illumination source such that reflected energy from both illumination sources can be recovered via filtering, said at least one structured illumination source and at least one unstructured illumination source having significantly overlapping spectral bands; for each of said captured images, comparing spatial characteristics of said reflection in said captured images to known spatial characteristics of undistorted projected patterns such that a spatial distortion of captured patterns can be characterized, said spatial distortion having been introduced by a reflection of said captured patterns off a surface of said target region; calculating a sequence of depth maps from said spatial distortion, in depth map being characterized for each of said captured images; for each depth map in said sequence of depth maps; determining spatial coordinates corresponding to said depth map; and estimating a 3D chest volume for each depth map in said sequence of depth maps; and calculating said subject'"'"'s chest volume using a proportionality constant which converts said estimated 3D volumes to an approximation of a measured chest volume as measured by laboratory tests. - View Dependent Claims (17, 18, 19)
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Specification