Image information read-out apparatus with circuit correcting for the influence of shading

An image information read-out apparatus comprising

• an analog image signal read-out means which causes a light beam to scan an image recorded on a recording medium and obtains an analog image signal representing the image,
• a first A/D convertor which has a dynamic range narrower than that of the analog image signal and digitizes the analog image signal,
• an offset means which gives to the analog image signal an offset of a predetermined width which is not smaller than the dynamic range difference between the dynamic range of the analog image signal and the dynamic range of the first A/D convertor and not larger than the dynamic range of the analog image signal,
• a second A/D convertor which has a dynamic range not narrower than the dynamic range difference and digitizes the analog image signal given the offset by the offset means, and
• an operator which adds the output of the second A/D convertor to the output of the first A/D convertor with the amount of the offset and the amount of the difference between the dynamic range of the first A/D convertor and the offset overlapping each other and subtracts the amount of the overlapping from the result of the addition.