Abstract: A specified lightness of a scanned image can be obtained by selecting from among plural gamma functions or by changing a light amount signal output by the line sensor of the scanning apparatus. Changing the light amount output may be accomplished by controlling the lighting time of each light source, or by adjusting the interval of a shift pulse of the line sensor, or by controlling the charge storage time of the line sensor. A controller adjusts the lighting time of the light source or the gradient of the gamma function in response to a specified lightness from an external computer so that image data in such specified lightness can be obtained. For example, in the case where the lightness is increased, if the user wishes a high quality image, the lighting time is increased, whereas if the user attaches importance to high speed reading, the gradient of the gamma function is increased.

Abstract: In a state where no original document is set, light emitted from a light source 6 is received by a sensor 5, a integrated light quantity reference value with which an output is made to be predetermined value V0 is obtained (P1), a magnification of the quantity of light and a gamma correction table are produced from gamma function data for prescanning (P2-1), a quantity of light for prescanning is obtained in accordance with a light quantity adjustment value obtainable from the magnification of the quantity of light and the integrated light quantity reference value and prescanning of a color negative film is performed (P2-2), and an image signal obtained by prescanning is converted with the gamma correction table so as to output image data (P2-3).

Abstract: This image reading apparatus includes: light sources, a line sensor for photoelectrically converting light from an original, a light source control section for controlling the lighting time of each light source; a gamma correction section for converting a photoelectrically converted electric signal to image data with a gamma function and a controller for controlling the light source control section and the gamma correction section. The controller adjusts the lighting time of the light source or the gradient of the gamma function in response to a specified lightness from an external computer so that image data in such specified lightness can be obtained. For example, in the case where the lightness is increased, if the user wishes a high quality image, the lighting time is increased, whereas if the user attaches importance to high speed reading, the gradient of the gamma function is increased.

Abstract: A data correction subsystem for a color image processing system having a color image reading device and a color image printing device. A chart file is transmitted to the printing device so that the printing device produces a sample chart. Calibration data is calculated from read sample data so that the read sample data can be corrected to corresponding data in the chart file. The read sample data is obtained by causing the reading device to read the sample chart. Printing data to be transmitted to the printing device is corrected using the calibration data.