The present invention relates to a method for detecting a person's fall by analyzing a stream of video images coming from an image taking device, comprising: .cndot. Acquisition (21) of successive images of a determined scene; .cndot. selecting (23, 25, 27) at least one point of the scene in said images; .cndot. determining the movement (29) of each selected point by analyzing the displacement of said point in the successive images in the form of a temporal succession of oriented vectors proportional to the instantaneous speed of movement of said point; .cndot. calculating (31) the instantaneous acceleration of each point associated with each vector representing the instantaneous speed; .cndot. detecting a fall (33) when the determined instantaneous speed is greater than a predefined threshold speed and the instantaneous acceleration is greater than a predefined threshold acceleration. 13 11. System for detecting a person's fall by analyzing a stream of video images, comprising: .cndot. a device (3) for acquiring successive images of a determined scene; .cndot. means for selecting at least one point of the scene in said images; .cndot. a calculator of the movement of each point selected by analysis of the displacement of said point in the successive images in the form of a temporal succession of oriented vectors proportional to the instantaneous speed of movement of said point; .cndot. a calculator of the instantaneous acceleration of each point associated with each vector representing the instantaneous speed; .cndot. means for detecting a fall when the determined instantaneous speed is greater than a predefined threshold speed and the instantaneous acceleration is greater than a predefined threshold accelerationLa présente invention se rapporte à un procédé de détection dechute d'une personne par analyse d'un flux d'images vidéo provenant d'undispositif de prise d'images, comprenant :.cndot. Acquisition (21) d'images successives d'une scène déterminée