A filtering process and an interpolating operation process are carried out in steps on an original image signal and, in the respective steps, a plurality of unsharp image signals are formed, which represent images having the same size as the size of the original image and have different frequency characteristics. Band-limited image signals are formed from the unsharp image signals and the original image signal, restricted by conversion, and integrated. An integration signal composed of predetermined frequency components of the original image signal is thereby formed. The frequency emphasis processing is carried out by multiplying the integration signal by an emphasis coefficient, and adding the resulting product to the original image signal. The dynamic range compressing process is carried out by converting a difference signal, which is obtained by subtracting the integration signal from the original image signal, and adding the converted difference signal to the original image signal. An artifact is thereby prevented from occurring at a region in the vicinity of an edge.