The invention discloses an image processing method which comprises the following steps: S1, establishing a ray image library of each layer of aluminum strand in a carbon fiber composite core wire forthe carbon fiber composite core wires of all models; S2, shooting a ray image of the to-be-detected carbon fiber composite core wire by adopting an X-ray machine; and S3, subtracting the ray image ofthe to-be-detected carbon fiber composite core wire from the ray image of each layer of aluminum strand of the carbon fiber composite core wire of the same model in the ray image library to obtain a ray image only containing the carbon fiber core rod. The invention further discloses a defect detection method adopting the image processing method. In addition, the invention further discloses a corresponding device and equipment and a computer storage medium. Interference formed by gaps of aluminum strands and the like of the wire can be effectively eliminated without using a developing agent, and defects of the carbon fiber composite core wire can be highlighted and displayed, so that the defects can be quickly and accurately identified and positioned.