A method for identifying contamination upon a lens of a stereoscopic camera, wherein said stereoscopic camera; • is arranged such, that a capturing area of said stereoscopic camera is predefined such, that a plurality of images from said stereoscopic camera have the same capturing area over time, • is provided with a first camera adapted to cover said capturing area by providing first images of said capturing area, and • is provided with a second camera adapted to cover said capturing area by providing second images of said capturing area, wherein said first images are divided into at least one evaluation area and said second images are divided into at least one evaluation area, wherein the respective evaluation area of said first and said second images (210, 220) are correspondently located in respective image (210, 220), wherein said method comprises the steps of; • forming historical image data for said evaluation areas, wherein said historical image data comprises an image parameter representing the respective evaluation area from a respective predetermined plurality of previously captured first and second images (210, 220), • comparing said historical image data for the evaluation area of said plurality of previously captured first images with historical image data for the evaluation area of said plurality of previously captured second images, and • indicating that at least one lens of said stereoscopic camera is contaminated, if a deviation larger than a threshold value between the compared historical image data is identified; • identifying a minimum value (Bmin1, Bmin2) and a maximum value (Bmax1, Bmax2) of said image parameter from said historical image data for each evaluation area, • calculating a first difference value between said minimum and said maximum value (Bmin1, Bmin2; Bmax1, Bmax2) for each evaluation area, • comparing said first difference value from the evaluation area of said first images with said first difference value from the evaluation area of said second images, and • identifying the evaluation area of said first or second images (210, 220) associated with the lowest first difference value as obstructed by contamination on the lens; wherein when a new first and second image (210, 220) has been captured by said stereoscopic camera, the method further comprises the steps of: • calculating an average value of said parameter of said historical image data for the respective evaluation areas of said first and second images (210, 220), • calculating a second difference value between said average values, • adding said second difference value to the parameter value from the evaluation area of a newly taken image in which the evaluation area is identified as obstructed. • is arranged such, that a capturing area of said stereoscopic camera is predefined such, that a plurality of images from said stereoscopic camera have the same capturing area over time, • is provided with a first camera adapted to cover said capturing area by providing first images of said capturing area, and • is provided with a second camera adapted to cover said capturing area by providing second images of said capturing area, wherein • forming historical image data for said evaluation areas, wherein said historical image data comprises an image parameter representing the respective evaluation area from a respective predetermined plurality of previously captured first and second images (210, 220), • comparing said historical image data for the evaluation area of said plurality of previously captured first images with historical image data for the evaluation area of said plurality of previously captured second images, and • indicating that at least one lens of said stereoscopic camera is contaminated, if a deviation larger than a threshold value between the compared historical image data is identified; • identifying a minimum value (Bmin1, Bmin2) and a maximum value (Bmax1, Bmax2) of said image parameter from said historical image data for each evaluation area, • calculating a first difference value between said minimum and said maximum value (Bmin1, Bmin2; Bmax1, Bmax2) for each evaluation area, • comparing said first difference value from the evaluation area of said first images with said first difference value from the evaluation area of said second images, and • identifying the evaluation area of said first or second images (210, 220) associated with the lowest first difference value as obstructed by contamination on the lens; • calculating an average value of said parameter of said historical image data for the respective evaluation areas of said first and second images (210, 220), • calculating a second difference value between said average values, • adding said second difference value to the parameter value from the evaluation area of a newly taken image in which the evaluation area is identified as obstructed.