There is a white calibration card at random, put it on the scanner's document feeder, turn on the scanner driver, click Calibration, and then automatically calibrate. There are also instructions on the CD.
PDF document scanned by scanner is distorted. How to correct it?
The PDF document scanned by the scanner is crooked, which can be solved by using OCR to identify the text in adobeacrobatprofessional.
The operation steps are as follows:
1. First open the PDF to be recognized, click Edit-Edit text and image for OCR recognition, as shown in the figure below, and then proceed to the next step.
2. Secondly, after completing the above steps, a single page will be recognized by default, but if you want to recognize the whole PDF file, please click the "Settings" button under "Scan Document" in the lower right corner of the figure, as shown in the figure below, and then go to the next step.
3. Then, after completing the above steps, in the pop-up window, check the item "All pages can be edited", click the "OK" button, click the edit picture to identify the whole article, as shown in the following figure, and then go to the next step.
4. Finally, after completing the above steps, adjust the content, as shown in the figure below. In this way, the problem is solved.
When scanning images with scanners, most operators only adjust options such as resolution and zoom ratio, and the rest adopt default settings. Practice has proved that this can not obtain the best scanning effect. Especially when the original image is defective, the scanning result is even less ideal. When scanning defective images, how can we give full play to the scanner's best performance and scan higher quality images? This requires careful analysis of the manuscript, full use of some manuscript correction functions provided by the scanner, and careful adjustment of the preset value of the scanner. First, adjust the brightness and contrast when scanning pictures that are not allowed to be exposed. Overexposed pictures look pale because of their high brightness; Underexposed pictures look black because of low brightness. At the same time, the image lacks levels and details. At this time, we can drag the slider on the brightness and contrast slider to make the brightness and contrast of the image moderate. Because the adjustment of brightness and contrast will affect all pixels in the image, we should be careful not to lose sight of one thing and lose sight of another. For example, the main information of a picture is located in a dark area, and brightening it can make the details more obvious. However, when the brightness level function is used to brighten all areas, all details in the areas with higher brightness will be lost. Second, the color balance should be adjusted when scanning color cast pictures. If the image is a bit off color, you can use the color balance option to change the overall tone of the image. When the color cast is not serious, you can choose the "automatic color balance" option to let the software automatically correct it; Manual adjustment should be made when the color cast is serious. The color of the scanner is mainly a mixture of red, green and blue. The scanner provides adjustment functions for these three basic colors respectively, and there are three sliding bars of red, green and blue in the adjustment options. To adjust the image color, simply drag the slider on the slider bar to the color you want to add to the image, or drag the slider away from the color you want to reduce. Color adjustment needs to master some knowledge of chromatics, especially the principle of complementary colors: two colors in relative positions on the color wheel are called a pair of complementary colors, such as red and cyan, green and magenta, and blue and yellow are complementary colors. The so-called complementarity means that the reduction of a color in an image will inevitably lead to the increase of its complementary color, and it is absolutely impossible for a color and its complementary color to increase or decrease at the same time. Thirdly, the gamma value should be adjusted when scanning the picture lacking layers, which will affect the tone of the middle value of the picture or the gray level of the middle layer. By adjusting the gray value, the brightness value of the gray level of the middle tone of the image can be changed, so as to improve the middle level of the image without having much influence on the levels of the dark part and the bright part. Entering a number greater than 1 will expand the range of midtones, which will result in less contrast and more details for images with larger midtones. Entering a number less than 1 will narrow the range of midtones, which will increase the contrast of the image and reduce the details of the image. The curve moves down, and the corresponding pixel of the image becomes dark; When moving up, the corresponding pixel becomes bright. Its adjustment often needs to be used in conjunction with brightness and contrast to achieve satisfactory results. Fourth, the pictures with unsatisfactory composition should be cut reasonably when scanning. The pictures with improper framing often have messy backgrounds, unclear themes or skewed scenery, and poor visual effects. When scanning, we can choose the scanning range as needed to select the original image, correct the skewed image and re-create the art. The specific operation is to select "scan size" as "custom" mode in the scan setting options, and then drag the selection box in the preview image window to select the area to be scanned. The method is: hold down the mouse Jian Zuo in one corner of the area to be scanned, drag the selection box to the opposite corner of the scanning area, and release the left button. In this way, the scanner will automatically scan only the selected area. Just use the "rotate" function to correct the skewed picture. 5. When scanning and printing pictures, you should use the function of eliminating moire fringes. In the field of printing, screen printing technology is adopted, which relies on countless dots of different sizes to express the brightness of images. These dots are acceptable to the naked eye, but it is a problem that cannot be ignored for the scanner, because the scanner will scan these dots when scanning the printed photos, which will affect the image quality. De-screening technology is to analyze the image with dots and restore it to the original image without dots, so as to reproduce the effect of the original image. Scanners generally have several options for us to choose from. Please select "magazine" when the original picture is a magazine or a film-covered printed matter; When the original picture is a newspaper or a rough dot print, please select "newspaper"; When the original picture is a high-quality exquisite print and the dot is small, please choose "art print". It should be noted that if you scan non-printed matter, you should select "Don't set" and don't turn on this function, because this will reduce the quality of scanned images. By modifying the scanning parameters, we can make up some shortcomings of the original image and improve the scanning effect appropriately, but the effect is always limited. The best way to get the ideal scanning effect is to choose a good picture. 6. Pictures downloaded from the Internet Because most of the pictures downloaded from the Internet are in RGB mode, and the color range of RGB mode is larger than that of CMYK mode, in order to ensure the printing effect of images, it is best to use RGB mode for processing and finally convert them into CMYK mode. When editing an image in RGB mode in photoshop, select the CMYK Preview option in the View menu. In other words, the image is edited in RGB mode and displayed in CMYK mode. Because most downloaded images are of display size, the area is very small. And when we want to make the image that the newspaper needs, this image will become unclear. If there are mosaics, you should pay more attention. Don't grind it too hard when grinding. We should blur it properly before sharpening it. If the original image is a color image, but it is to be used for grayscale layout, do not edit the original image directly into grayscale mode during processing. RGB mode should be used for processing. First, the processed image should be converted into L*A*B* mode image, and then the image of L* channel should be selected as the printed grayscale image through the channel separation command. Be careful not to switch between RGB and CMYK modes, let alone between these two modes, because in the dot matrix image editing software, every time the image color space is converted, some details of the original image will be lost. Matters needing attention in newsprint printing image processing: in order to make the color bright, the main color should be appropriately increased, and the opposite color should be appropriately reduced or not used; Discard the dark tone appropriately and keep the medium light tone; The face value of people's black and white images should not be too high, so as not to be too dark, and the bright colors should be enough. In a word, I have a deep understanding and experience in image scanning and production in prepress system.