Analysis of Image Scanning Quality Control

The most basic job of printing is copying colors, which are often expressed through pictures. Image scanning is to convert the color information on a picture to a storable and editable digital signal through a scanning device, and then process these digital signals through application software such as image processing software and typesetting software. Therefore, whether or not the image can be accurately reproduced with high quality, ie, the information such as tone, gradation, contrast, and saturation on the original as much as possible, is a basic standard for measuring the quality of image scanning. Printed manuscripts can be classified into reflective and transmissive manuscripts. Among them, reflective drafts are divided into photographs, prints, hand-drawn drafts, and drafts, etc.; transmissions are divided into positive and negative films. Since each type of manuscript has its own different characteristics, the characteristics of each manuscript must be fully taken into account when scanning the calibration.

Image scan quality evaluation:

(1) accurate calibration

Accurate calibration of the original document is the basis for the true restoration of the original, because it is related to the size of the entire image contrast and how much loss of highlights, dark tone and other issues. For example, for a transmitted original, if the contrast of the original is normal, the white field should be selected at a density of D: 0.35-0.50; if the original is thin, the amount of color needs to be increased, and the white field should generally be selected at a density of D: 0.20. - 0.35; If the original is more boring, need to be brighter, white field should generally choose the density D: 0.60-0.80. (2) Complete adjustment and high resolution

Tonality is the hierarchical structure of the entire picture. A complete tone can make the picture complete, because it is easy to lose the level in the darkest place and the brightest place, especially in the edge area of ​​a large area composed of pale white, this situation is more likely to occur. If the tone is the body of image color reproduction, then the clarity of the image can be said to be the soul of image reproduction. Sharpness can focus on vision: whether an image is clear is the most important factor in whether it can attract attention.

(3) faithful manuscripts, higher than manuscripts

When the manuscript has a rich gradation, strong contrast, and high saturation, it is sufficient to restore the gradation, contrast, and saturation of the original as accurately as possible during scanning. When the quality of the original is not very good, and sometimes there is even a clear cast color or low saturation, attention should be paid to the adjustment during scanning, so that the scanned image is more real and bright than the original.