Ein eine Abbildung bildendes Gerät für eine Halbton-Aufzeichnungs- und -Schattierungs-Kompensation und ein eine Halbton-Abbildung bildendes Verfahren

摘要

An image forming apparatus is described including a white reference body and an image sensing means for scanning the reference body or a document to produce digital pixel data. The CPU of the apparatus controls the image sensing means to scan the reference body to produce analogue image data, converted to digital pixel data by an ADC. For each pixel, the CPU determines a shading factor by dividing a predetermined maximum brightness value by the digital pixel data. The CPU also controls the image sensing means to scan a document to produce analogue image data, again converted to digital pixel data by the ADC. For each pixel, the CPU determines shading-compensated pixel data by multiplying the digital pixel data by the corresponding shading factors. Finally, a half tone image of the scanned document is produced from the shading-compensated pixel data.