A method of detecting defects on a fiber material surface of a fiber material which is a component of a fiber composite material comprising the fiber material and a matrix material embedding the fiber material by an optical detection system, the method comprising the following steps: - Detection of the fiber material surface of the deposited fiber material by means of at least one optical sensor of the optical detection system and generation of digital image data containing the detected fiber material surface; - Performing a first machine classification method based on the generated digital image data by means of an electronic data processing apparatus of the optical detection system, wherein the first machine classification method detects defects in the digital image data containing the fiber material surface and classifies the type of defects as a detection result; characterized by - Performing at least one second machine classification method different from the first machine classification method based on the same generated digital image data by means of the electronic data processing apparatus of the optical detection system, wherein the second machine classification method detects defects in the digital image data containing the fiber material surface and classifies the type of defects as a detection result; - comparing the detection results of the defect detection and/or intermediate results thereof of the first machine classification method and the second machine classification method by means of the electronic data processing apparatus; - Detecting a defect and classifying the type of defect on the fiber material surface of the deposited fiber material depending on the comparison of the detection results by means of the electronic data processing apparatus. - Detection of the fiber material surface of the deposited fiber material by means of at least one optical sensor of the optical detection system and generation of digital image data containing the detected fiber material surface; - Performing a first machine classification method based on the generated digital image data by means of an electronic data processing apparatus of the optical detection system, wherein the first machine classification method detects defects in the digital image data containing the fiber material surface and classifies the type of defects as a detection result; - Performing at least one second machine classification method different from the first machine classification method based on the same generated digital image data by means of the electronic data processing apparatus of the optical detection system, wherein the second machine classification method detects defects in the digital image data containing the fiber material surface and classifies the type of defects as a detection result; - comparing the detection results of the defect detection and/or intermediate results thereof of the first machine classification method and the second machine classification method by means of the electronic data processing apparatus; - Detecting a defect and classifying the type of defect on the fiber material surface of the deposited fiber material depending on the comparison of the detection results by means of the electronic data processing apparatus.