Image analysis for smoke detection

A smoke detector that identifies, in a current input image, an area indicative of the presence of smoke, there being a sequence of two or more input images, said detector comprising:

• a memory that stores a background estimation as one of said input images;
• a comparator that compares said current input image with said background estimation to detect a partial obscuring of said background estimation indicative of the presence of smoke in said current input image,
• an estimator that forms an estimate of a color of and a degree of said partial obscuring of said background estimation in dependence on said current input image and said background estimation;
• an updating unit that updates said background estimation in accordance with said current input image and said background estimation;
• and
• a reconstructing unit that forms a reconstructed background from said current input image, said estimate of said color of said partial obscuring of said background estimation and said estimate of said degree of said partial obscuring of said background estimation, said updating said background estimation comprising forming a linear combination of said current input image, said background estimation and said reconstructed background estimation.

A non-transitory computer-readable medium having stored thereon computer program code that when executed by a computer causes a processor of the computer to execute a smoke detection method for identifying, in a current input image, an area indicative of the presence of smoke, there being a sequence of two or more input images, said method comprising:

• initializing a background estimation as one of said input images;
• comparing said current input image with said background estimation to detect a partial obscuring of said background estimation indicative of the presence of smoke in said current input image;
• forming an estimate of a color of and a degree of said partial obscuring of said background estimation in dependence on said current input image and said background estimation;
• updating said background estimation in accordance with said current input image and said background estimation;
• and
• forming a reconstructed background from said current input image, said estimate of said color of said partial obscuring of said background estimation and said estimate of said degree of said partial obscuring of said background estimation, said updating said background estimation comprising forming a linear combination of said current input image, said background estimation and said reconstructed background estimation.

A smoke detection method for identifying, in a current input image, an area indicative of a presence of smoke, there being a sequence of two or more input images, said method comprising:

• initializing a background estimation as one of said input images;
• comparing said current input image with said background estimation to detect a partial obscuring of said background estimation indicative of the presence of smoke in said current input image;
• forming an estimate of a color of and a degree of said partial obscuring of said background estimation in dependence on said current input image and said background estimation;
• updating said background estimation in accordance with said current input image and said background estimation;
• updating said background estimations being arranged such that said current input image contributes to each of said updated background estimations to different respective degrees, said comparing comprising comparing said current input image with each of said background estimations;
• and
• forming a smoke probability map in dependence upon a comparison of said current input image and said background estimation, each value of said smoke probability map indicating a probability that a corresponding location in said current input image is indicative of the presence of smoke, in which a value of said smoke probability map is derived from said background estimation that results in a lowest probability.

A smoke detector that identifies, in a current input image, an area indicative of the presence of smoke, there being a sequence of two or more input images, said detector comprising:

• a memory that stores a background estimation as one of said input images;
• a comparator that compares said current input image with said background estimation to detect a partial obscuring of said background estimation indicative of the presence of smoke in said current input image,
• an estimator that forms an estimate of a color of and a degree of said partial obscuring of said background estimation in dependence on said current input image and said background estimation;
• an updating unit that updates said background estimation in accordance with said current input image and said background estimation;
• the updating unit further updates said background estimations being arranged such that said current input image contributes to each of said updated background estimations to different respective degrees, said comparing comprising comparing said current input image with each of said background estimations
• a mapping unit that forms a smoke probability map in dependence upon a comparison of said current input image and said background estimation, each value of said smoke probability map indicating a probability that a corresponding location in said current input image is indicative of the presence of smoke, in which a value of said smoke probability map is derived from said background estimation that results in a lowest probability.

A non-transitory computer-readable medium having stored thereon computer program code that when executed by a computer causes a processor of the computer to execute a smoke detection method for identifying, in a current input image, an area indicative of the presence of smoke, there being a sequence of two or more input images, said method comprising:

• initializing a background estimation as one of said input images;
• comparing said current input image with said background estimation to detect a partial obscuring of said background estimation indicative of the presence of smoke in said current input image;
• forming an estimate of a color of and a degree of said partial obscuring of said background estimation in dependence on said current input image and said background estimation;
• updating said background estimation in accordance with said current input image and said background estimation;
• updating said background estimations being arranged such that said current input image contributes to each of said updated background estimations to different respective degrees, said comparing comprising comparing said current input image with each of said background estimations;
• and
• forming a smoke probability map in dependence upon a comparison of said current input image and said background estimation, each value of said smoke probability map indicating a probability that a corresponding location in said current input image is indicative of the presence of smoke, in which a value of said smoke probability map is derived from said background estimation that results in a lowest probability.