Forging is the process of making and shaping metals by use of hammering or pressing. Forging is one of the main processes in metal production. To keep the quality of forged parts high is very important from the viewpoint of performance or safety of the products. Hence forged part quality is checked by visual inspection whether there is any defect, it imposes a lot of loads to the workers. Same way the defect detection is expected to be substituted by laser measurement or image processing instead of human eyes, comparison of both methods has hardly been carried out. In this , experimental results to detect defects by both methods are described for one forged part. Mainly, comparison between frequency analysis by Fourier or wavelet transform and image processing is reported.