Method of raindrop detection on a vehicle windscreen and driving assistance device

Method of raindrop detection on a vehicle windscreen by capturing images using a camera which is at least focused on the windscreen, including a step of detecting edges (102) in a research area of said captured images, characterized in that said method of raindrop detection comprises a rejection step (103) in which edges that are uncharacteristic with respect to a raindrop are rejected, this rejection step (103) comprises at least the following sequence :

• a first stage (103a) where closed edges are selected while unclosed edges are rejected,
• a second stage (103b) where among the remaining selected closed edges, connected components are extracted,
• a third stage (103c) where among the extracted connected components, extracted connected components that have geometric criteria different from raindrop ones are rejected,
• a fourth stage (103d) where among the remaining extracted connected components, extracted connected components that are inclined over a predetermined angle threshold are rejected,
• a fifth stage (103e) where among the remaining extracted connected components, extracted connected components showing a grey level variation different from the raindrop grey level variation having one minimum and one maximum, are rejected,
• a sixth stage (103f) where among the remaining extracted connected components, extracted connected components having a predetermined pixels number with a grey level higher than a predetermined grey level threshold are rejected, and then
• a seventh stage (103h) where among the extracted connected components rejected by said sixteen stage (103f), if more than two rejected extracted connected components are detected within a predetermined distance threshold in a critical research area, extracted connected components between them are rejected.