Extraction of film image parameters in image processing apparatus

An image processing apparatus comprising:

• image reading means for reading an image of a film to produce color decomposition data by scanning a plurality of lines on the film image in a stepped prescanning operation;
• memory means;
• and
• parameter extracting and setting means for, during the prescanning operation, sampling and adding the color decomposition data of a plurality of pixels at each of a first plurality of sampling points on a line-by-line basis and averaging the added color decomposition data, corrections including a shading correction being performed concurrently with the adding and averaging of the color decomposition data, and for, during a period of from an end of the prescanning operation to a start of a main scanning operation, from the averaged color decomposition data, determining a density correction amount and responsive to said density correction amount calculating parameters to be used for correcting the film image in a succeeding actual image processing operation, and setting the calculated parameters in the memory means.