How Does a Scanner Improve Image Scanning Quality

The ScanMaker 4800i is a powerful scanner. Added full support for Excel spreadsheet files and automatic identification of color documents. The latest software, Scan Wizard 5, comes with two different control panels.

Whether using a roller scanner or a flatbed scanner, it is necessary to master certain scanning techniques in order to obtain the ideal scanning image quality.

Even if you use the same scanner to scan the same image, the effect of the scanned image may sometimes be very different. There are many factors that affect the quality of the scanned image. Apart from the resolution and scaling ratio, it also has a very close relationship with the scan driver software used by the user. How can we improve the scanning quality of the image, I believe that the following aspects should attract attention.

Correctly select the type of scan

At present, the types of scanning are color, grayscale, black and white, and should be selected according to specific requirements. There is no doubt that the black-and-white image is selected in black and white (or Line Art), but if there is a color image, the end result is a gray-scale image. Is the user scanning in grayscale or color? The author's suggestion is to use color scanning. Selecting the color scan can make various adjustments to the scanned original. At the same time, the color information of the color scan is large, and the colors obtained after the scan are more full and more abundant. Then use the image processing software to convert the color image into a grayscale image. Although the color is lost, the level remains more. In contrast, if grayscale scanning is directly selected, the color of the image before scanning is lost, and the margin for adjustment is very small. After scanning, the level of the grayscale image is obviously not rich in the level of color scanning and then converted into a grayscale image.

Select a good scan original

The quality of the scanned document will directly affect the quality of the scanned image. Selecting a good scanned document is very important for the user. People usually have a misunderstanding that they can obtain high-quality images by using the professional image processing software to repair the problems that appear in the scanned image after the scanned image. In fact, this is only one aspect of the problem; you cannot correct scanned images with only a small amount of information. The function of the image processing software can hardly be overwhelming, and no more levels can be corrected. Correcting the original, although it can make up for some defects in the original, the quality of the scanned image is always better than the original. Therefore, selecting high-quality original scanning is the shortest path, prerequisite and guarantee for obtaining high-quality images.

Correct the original as needed

As already mentioned above, manuscripts are the basis and basis for scanning. Only high-quality manuscripts can make scanned images have more levels. However, the actual situation is that many manuscripts have large problems such as color cast, Lack of levels, faintness, strong graininess, etc. Therefore, in order to obtain high scanning quality, the user first needs to correct the original in a targeted manner according to specific conditions.

When the scanned image is used for advertising, it must be very appealing and usually requires vivid colors, bright colors, and saturation as much as possible. In this case, the saturation of the original should be enhanced. When the quality of the original document is basically approved, if you just want to highlight a part of the details, you need to make fine adjustments to the original, you can change the contrast and brightness, but do not have to sharpen, there is no need to use a blurred image. If the image of the original is blurred, the sharpening function can be selected, but the distribution of the scanned image's color gradation should be checked, and if a fault occurs, this function should not be used. If the image has a color cast, it can be visually judged by humans. When a bright-tone image has only one color cast, because human perception is non-linear, it is easier for humans to identify the unreal tone in bright tone than bright tone. According to the color of the object and its surroundings, the human eye can easily see the color cast.

Determine the original black and white field

In order to better highlight the part of the manuscript that needs to be scanned most, the choice of black and white fields is also very necessary. Its purpose is to subtly adjust the brightness level of the image. Black field refers to the darkest place in the manuscript, but it is not necessarily the darkest place in the manuscript. White field refers to the brightest place in the original, but it is not necessarily the brightest place in the manuscript. If the brightest part of the manuscript has no hierarchy, it should not be selected as a white field, and vice versa. In general, the density range between black and white fields covers all levels of the original, so black and white fields should be selected in the main part of the original document that needs to be scanned. For example, a color photograph, which includes people and landscapes, should in principle be selected on the portraits of people in black and white fields. In order to highlight the main characters, they should generally not be selected as scenery on the back.

In a grayscale image of a single object, the white field is usually clearly indicated, but it is more difficult for color images because each image has three (RGB) or four (CMYK) different tone values, which are easy to confuse. Human eyes. It is very difficult to accurately point out the dark field in a manuscript with very dark or very bright details. It is generally necessary to use professional tools to judge, such as the straw tool.

In comparison, the choice of Whitefield is even more important. It has the greatest influence on scanning of the highlights and midtones of the original. And these two parts are usually regarded as the tone of the original, which directly affects the level and color of the image. Therefore, the selection of the white field must be very careful, you can choose more than a few white fields, try to scan, determine a suitable white field after comparison. If the black and white fields can be correctly selected, the scanned image will be very clear, evenly distributed, and clearly structured.

Sharpening of the image

When the user is satisfied with the scanned image, it is best to do a sharpening process in the image processing software. This is due to the limitations of the light-receiving components (such as the CCD and its optical quality and lighting conditions, etc.) and quantization errors caused by digital sampling. Scanned images are often not as clear as the original or in-kind. Therefore, in image processing, it is important to increase the clarity of the scanned image by artificially processing, such as Unsharp, Sharpen, and Sharpen More.

The author's experience is that in the professional field of color desktop publishing system, prepress system, advertising design, light printing, packaging industry and other professional fields, to obtain the ideal scanning image quality, it is necessary to correct the original by the above aspects.

Source: Ke Yin Network