IMAGE SCANNER DEVICE

PURPOSE:To improve a relative density resolution by using a maximum lightness of color in a variable lightness of images or using a designated area a maximum lightness to form a look up table (LUT) and inputting a binary data to this table to resolve a density. CONSTITUTION:An image data obtained from a sensor 2 is converted into multi- value digital data A by an analog/digital converter (A/D) 3 and stored once in a frame memory 4. Image data stored in the frame memory 4 is displayed on a monitor 9 and inputted to an average density calculating circuit 5. In the average density calculating circuit 5, an average value of the image data in an area designated by operating a digitizer 8 and desired to be the maximum lightness of color in the displayed image on the monitor 9 is calculated and the value Dmax is transmitted to a converting table forming circuit 6. Namely, the variable density image is read, converted to the image data of 8 bits in a look up table (LUT) circuit 7. When inputting into a computer system, for example an average value of the area desired to be the maximum lightness in the density images is made a reference value of the look up table (LUT).