Method for assessing the reliability of an object detection unit, programmed to detect images of objects and their positions and object types in two or three-dimensional images (A, A') provided to the object detection unit by using an object detection and/or a classification method, in particular a neural network, comprising the following steps: - a diagnostic unit selecting at least one reference object (R; R 1, R 2, R 3) with a known object type wherein the image of said reference object (R; R 1, R 2, R 3) is to be detected by the object detection unit, - the diagnostic unit providing at least one test image (A'), in particular in a predefined sequence of images and/or in a random way, to the object detection unit, wherein said test image (A') contains the image of the reference object (R; R 1, R 2, R 3) at a known position (P; P 1, P 2, P 3), - the diagnostic unit defining a tolerance margin around the known position (P; P 1, P 2, P 3) of the reference object (R; R 1, R 2, R 3) for acceptable detection of the position of said reference object (R; R 1, R 2, R 3) in the test image (A'), - detecting the image of at least one object and its position and object type in the test image (A') with the object detection unit, - the diagnostic unit comparing the known position (P; P 1, P 2, P 3) and object type of the reference object (R; R 1, R 2, R 3) with the detected position and object type of the detected object, and - the diagnostic unit determining the object detection unit to be reliable if ∘ the object type of the reference object (R; R 1, R 2, R 3) corresponds to the object type of the detected object and ∘ the detected position of the detected object, in particular a detection margin (M') around the detected position, lies substantially within the before defined tolerance margin around the known position (P; P 1, P 2, P 3) of the reference object (R; R 1, R 2, R 3). - a diagnostic unit selecting at least one reference object (R; R 1, R 2, R 3) with a known object type wherein the image of said reference object (R; R 1, R 2, R 3) is to be detected by the object detection unit, - the diagnostic unit providing at least one test image (A'), in particular in a predefined sequence of images and/or in a random way, to the object detection unit, wherein said test image (A') contains the image of the reference object (R; R 1, R 2, R 3) at a known position (P; P 1, P 2, P 3), - the diagnostic unit defining a tolerance margin around the known position (P; P 1, P 2, P 3) of the reference object (R; R 1, R 2, R 3) for acceptable detection of the position of said reference object (R; R 1, R 2, R 3) in the test image (A'), - detecting the image of at least one object and its position and object type in the test image (A') with the object detection unit, - the diagnostic unit comparing the known position (P; P 1, P 2, P 3) and object type of the reference object (R; R 1, R 2, R 3) with the detected position and object type of the detected object, and - the diagnostic unit determining the object detection unit to be reliable if ∘ the object type of the reference object (R; R 1, R 2, R 3) corresponds to the object type of the detected object and ∘ the detected position of the detected object, in particular a detection margin (M') around the detected position, lies substantially within the before defined tolerance margin around the known position (P; P 1, P 2, P 3) of the reference object (R; R 1, R 2, R 3). ∘ the object type of the reference object (R; R 1, R 2, R 3) corresponds to the object type of the detected object and ∘ the detected position of the detected object, in particular a detection margin (M') around the detected position, lies substantially within the before defined tolerance margin around the known position (P; P 1, P 2, P 3) of the reference object (R; R 1, R 2, R 3).