A laser system and techniques which compensate for laser fluence drop off or losses of irradiation as an ablating laser beam is traversed on a curved surface. For a smear occurred at the charge transfer portion, reference smear amount data is stored, corresponding to each of color components of light from the light emitting portion and a correction target pixel. The image data, whose polarity is reversed by the polarity reversing circuit, is written into the each of the plurality of pixels.