Abstract: The invention concerns a method and a system for detecting a body (801) in a zone (802) located proximate an interface (803). The body is illuminated by an electromagnetic radiation (804) comprising at least two different wavelengths, located in ranges corresponding to near infrared and to green-blue. The method comprises the following steps: selecting two wavelengths; providing, for each of said wavelengths, an image (805) of the interface and of the zone; extracting from said data of each image two sets of data (807) respectively representing at least one part of the body in the near infrared range and in the green-blue range; comparing said data sets (807). It is thus possible to detect the presence of a body by discriminating between a body entirely located beneath the interface and a body located at least partly above the interface.

Abstract: A method and system for detecting an object in a zone located proximate to an interface between two liquid and/or gaseous media having different refractive indices, for example of the air/water type. The method and system produce at least a video image of the interface and the zone and produces electric signals representing each video image. Then, the electric signals are digitized and the data is processed by discriminating the data corresponding to the video image of the real object from those corresponding to the apparent video image generated by the interface.

Abstract: The invention concerns a method and a system for detecting a body (801) in a zone (802) located proximate an interface (803). The body is illuminated by an electromagnetic radiation (804) comprising at least two different wavelengths, located in ranges corresponding to near infrared and to green-blue. The method comprises the following steps: selecting two wavelengths; providing, for each of said wavelengths, an image (805) of the interface and of the zone; extracting from said data of each image two sets of data (807) respectively representing at least one part of the body in the near infrared range and in the green-blue range; comparing said data sets (807). It is thus possible to detect the presence of a body by discriminating between a body entirely located beneath the interface and a body located at least partly above the interface.

Abstract: The invention relates to a method for detecting an object (1) in relation to a surface (2). A synthetic image (3c, 4c) is produced from at least two distinct viewpoints (3, 4), for each of said viewpoints, by means of a geometrical transformation comprising at least one perspective projection (3a, 4a) of the object on the surface (2), each synthetic image being associated with the viewpoint concerned. By discriminating between the synthetic images, it is possible to detect the presence of and determine the position of the object (1) in relation to the surface (2), by searching for contrast inversions. The invention can be used for surveying a swimming pool.

Abstract: A method and system for detecting an object in a zone located proximate to an interface between two liquid and/or gaseous media having different refractive indices, for example of the air/water type. The method and system produce at least a video image of the interface and the zone and produces electric signals representing each video image. Then, the electric signals are digitized and the data is processed by discriminating the data corresponding to the video image of the real object from those corresponding to the apparent video image generated by the interface.

Abstract: The invention concerns a warning system to help preventing drowning accidents. The system comprises at least a sonar (1). Each sonar (1) comprises at least a transmission antenna and a reception antenna having transmission (4) and reception (5) apertures. The sonar (1) is a parametric sonar with high spatial directive gain along said transmission (4) and/or reception (5) apertures. The angular opening of the transmission (17) and/or reception (18) lobes of said transmission and/or reception antennae is of the order of one degree or less than one degree. The system comprises a processing calculator. The sonar (1) comprises amplifier means and transmission means for amplifying and transmitting the electric signals coming from said reception antenna.

Abstract: The invention relates to a method for detecting an object (1) in relation to a surface (2). A synthetic image (3c, 4c) is produced from at least two distinct viewpoints (3, 4), for each of said viewpoints, by means of a geometrical transformation comprising at least one perspective projection (3a, 4a) of the object on the surface (2), each synthetic image being associated with the viewpoint concerned. By discriminating between the synthetic images, it is possible to detect the presence of and determine the position of the object (1) in relation to the surface (2), by searching for contrast inversions. The invention can be used for surveying a swimming pool.