1. A method of inspecting surface conditions of an object with a curved surface placed on a reference plane, said method comprising the steps of: obtaining an image from reflected light from said curved surface irradiated by a light including a plurality of color components having different colors projected from different directions with respect to said reference plane; carrying out, within an image area in the obtained image, an extracting process by extracting for each pixel the brightness of a white component generated by mixing all of said color components and a brightness-reducing process by reducing the brightness of each of said color components of each pixel by an amount corresponding to the extracted brightness of the white component of the pixel; carrying out, from each pixel of said image area for which said brightness-reducing process has been carried out, a brightness-restoring process by varying the brightness of each of said color components such that the brightest of said color components becomes more strongly emphasized compared to the others of said color components than before said brightness-reducing process and the loss in total brightness caused by said brightness-reducing process is restored; and carrying out an inspection of surface conditions of said curved surface based on a distribution of said color components in said image after said brightness-restoring process.