| 摘要 |
Disclosed is a method for controlling processes during printing. In order to determine the tint value (R) of a sector of a printing substrate, a digital image of said substrate sector is recorded, a frequency distribution of the grayscale values of the pixels is determined from said image, a minimum frequency is determined as a threshold value (GG)of the grayscale value in the central range of the grayscale value from said frequency distribution, and the pixels located on one side of said threshold value are counted as covered while the pixels located on the other side are counted as free so as to calculate the tint value (R) of the substrate. Also disclosed is an image-recording apparatus for recording images of different printing substrates on which the inventive method can be carried out. Said image-recording apparatus comprises an electronic camera module, an imaging lens that is disposed in front of said electronic camera module, and a device (3) for illuminating the substrate. Said illuminating device (3) encompasses both a bright field light source (4) and a dark field light source (6) which can be activated independently of each other and whose luminous intensity can be adjusted, respectively. |
