IMAGE INFORMATION READ-OUT APPARATUS WITH CIRCUIT CORRECTING FOR THE INFLUENCE OF SHADING

In an image information read-out apparatus, a light beam scans an image recorded on a recording medium and an analog image signal representing the image is obtained. A logarithmic amplifier for logarithmic transformation of the analog image signal has certain characteristics in that a nonlinear portion of its range is in a dynamic range of the analog image signal. An A/D convertor digitizes the analog image signal transformed by the logarithmic amplifier and obtains a digital image signal. A correction circuit corrects the digital image signal so that the influence of shading is cancelled and linearly interpolates the part of the digital image signal corresponding to the nonlinear portion of the characteristics of the logarithmic amplifier on the basis of the characteristics of the shading and the characteristics of the nonlinear portion of the characteristics of the logarithmic amplifier, which have been obtained in advance.