A one camera monitoring method, comprising: exposing an image frame of an object to be monitored by an area image sensor (10, 31, 41); transmitting an image part of said image frame to an image data processing device; analysing said image part by said image data processing device (32, 42), characterised in that; - if said image part is detected to comprise at least one predefined event of at least two different predefined events, said image data processing device (32, 42) is arranged to transmit a trigger signal for triggering said area image sensor (10, 31, 41) so that said area image sensor (10, 31, 41) is reconfigured to expose a further image frame and to transmit an image part of said further image frame to said image data processing device (32, 42) for further analysis, wherein the image part of said further image frame is bigger than the image part of said image frame, and wherein each of said at least two predefined events is configured to determine a particular size and position for the image part of said further image frame, and - if said image part is not detected to comprise a predefined event of said at least two different predefined events, said area image sensor (10, 31, 41) continues back to expose an image frame of the object to be monitored and to transmit an image part of said image frame to the image data processing device (32, 42). exposing an image frame of an object to be monitored by an area image sensor (10, 31, 41); transmitting an image part of said image frame to an image data processing device; analysing said image part by said image data processing device (32, 42), characterised in that; - if said image part is detected to comprise at least one predefined event of at least two different predefined events, said image data processing device (32, 42) is arranged to transmit a trigger signal for triggering said area image sensor (10, 31, 41) so that said area image sensor (10, 31, 41) is reconfigured to expose a further image frame and to transmit an image part of said further image frame to said image data processing device (32, 42) for further analysis, wherein the image part of said further image frame is bigger than the image part of said image frame, and wherein each of said at least two predefined events is configured to determine a particular size and position for the image part of said further image frame, and - if said image part is not detected to comprise a predefined event of said at least two different predefined events, said area image sensor (10, 31, 41) continues back to expose an image frame of the object to be monitored and to transmit an image part of said image frame to the image data processing device (32, 42). - if said image part is detected to comprise at least one predefined event of at least two different predefined events, said image data processing device (32, 42) is arranged to transmit a trigger signal for triggering said area image sensor (10, 31, 41) so that said area image sensor (10, 31, 41) is reconfigured to expose a further image frame and to transmit an image part of said further image frame to said image data processing device (32, 42) for further analysis, wherein the image part of said further image frame is bigger than the image part of said image frame, and wherein each of said at least two predefined events is configured to determine a particular size and position for the image part of said further image frame, and - if said image part is not detected to comprise a predefined event of said at least two different predefined events, said area image sensor (10, 31, 41) continues back to expose an image frame of the object to be monitored and to transmit an image part of said image frame to the image data processing device (32, 42).