Unobtrusive remote monitoring device for extracting physiological information that is representative of at least one at least partially periodic vital signal from detected characteristic signals, the device comprising: - an interface arranged for receiving a data stream that comprises a sequence of image frames derivable from electromagnetic radiation emitted or reflected by an object, the data stream comprising a continuous or discrete characteristic signal including physiological information that is indicative of desired object motion, - an extractor means arranged for extracting the physiological information from the data stream by deriving a sequence of characteristic index elements from the sequence of image frames through a dimensional reduction applied to the image frames, the plurality of characteristic index elements comprising a directional motion component that is associated with a disturbance-reduced index element that has a determined orientation substantially aligned with a reference motion direction and that describes a preferential direction of object motion indicative of the at least one at least partially periodic vital signal, such that the sequence of characteristic index elements is indicative of a derivative signal form comprising the physiological information, wherein the dimensional reduction comprises agglomerating and projecting data stream properties associated with respective pixel sub-entities (62, 64) of the image frames comprised in the data stream onto the disturbance-reduced index element, thereby obtaining the respective characteristic index element, such that motion information indicative of the desired signal to be extracted is still contained in the resulting characteristic index elements, and - an analyzing means arranged for determining a temporal variation of the derivative signal form, wherein the temporal variation corresponds to the at least one at least partially periodic vital signal. - an interface arranged for receiving a data stream that comprises a sequence of image frames derivable from electromagnetic radiation emitted or reflected by an object, the data stream comprising a continuous or discrete characteristic signal including physiological information that is indicative of desired object motion, - an extractor means arranged for extracting the physiological information from the data stream by deriving a sequence of characteristic index elements from the sequence of image frames through a dimensional reduction applied to the image frames, the plurality of characteristic index elements comprising a directional motion component that is associated with a disturbance-reduced index element that has a determined orientation substantially aligned with a reference motion direction and that describes a preferential direction of object motion indicative of the at least one at least partially periodic vital signal, such that the sequence of characteristic index elements is indicative of a derivative signal form comprising the physiological information, wherein the dimensional reduction comprises agglomerating and projecting data stream properties associated with respective pixel sub-entities (62, 64) of the image frames comprised in the data stream onto the disturbance-reduced index element, thereby obtaining the respective characteristic index element, such that motion information indicative of the desired signal to be extracted is still contained in the resulting characteristic index elements, and - an analyzing means arranged for determining a temporal variation of the derivative signal form, wherein the temporal variation corresponds to the at least one at least partially periodic vital signal.