Image digitization problem

In the process of digitally scanning and processing the image, a detailed understanding of the image processing system and image processing requirements is required.

First, the necessary tools and software

1. Scanner: When selecting the scanner, be sure to combine the original type, the final image use, and the scanner's scanner characteristic parameters: dynamic density range, scanned web, resolution, and the ability to scan software and transmissive document scans. consider.

2. Digital Camera: When selecting a digital camera, only these devices can record static plane images. At the same time, a more important issue is to consider the resolution of digital cameras.

3. Duplicators: There is now a duplicator connected to a computer that can also be used to digitize images. What this type of copying machine does is the role of the scanner.

4, color management system: In the digital image, if there is a color management system, we can get intuitive and vivid WYSIWYG results. However, there is a difference between the screen color gamut and the monitor color gamut, so pay attention to this.

5, file format: The file format, to consider what kind of file format storage is suitable for the use of post-process and other software.

6, storage equipment: What kind of storage device for storage. Is the use of floppy disks, removable hard drives, tapes, MOs, CD-ROMs, DVDs, or other forms of storage.

Second, consider the issue of feature setting in image digitization and processing

1. How do you choose to convert from RGB color space to CMYK color space?

Is it a direct conversion or image processing software used in the scanning process? If you are using a high-end scanner or a scanner specialized in prepress development, you can use the color space conversion format directly in the scanning process; But for the color conversion of the low-grade scanner, it is best to choose a good image processing software for color conversion.

And when converting RGB to CMYK, it is important to consider the printing characteristics of paper, ink, and printing presses.

2. How to set the scan resolution to be correct?

The scanning resolution setting of the image generally has a calculation method: that is, using the number of final printed screens multiplied by the magnification of the image, multiplied by a factor of a value between 1.5-2, the resulting number can be Scan resolution was used.

When dealing with text and lines, to avoid jaggies, the resolution set is generally much higher than the scanning resolution of the image. Equal line or text resolution is between 600-1200 dpi.

When setting the resolution, it is also important to note that if the calculated resolution exceeds the scanner's maximum optical resolution, it can only be done using the maximum optical resolution scan. If the resolution of the text or line image does not meet the requirements, then interpolation can be used to make up for it. However, continuously adjusting the image can only control the zoom ratio of the image, otherwise a mosaic effect may occur.

3, how to deal with two-tone image?

4. Is the image size correct?

5, the image of the various conversion, such as size changes, cutting processing, rotation changes and group image combination process, it is best to complete in the image editing software. Otherwise it will affect the output speed and memory usage when outputting.

6. Is the image compressed?

Images that are typically used for printing are not compressible because the compression of the image can cause loss of image detail. However, when TIFF files are stored, a lossless compression format called LZW can be used, which does not lose detail on the image. However, it also does not advocate the use. Because, in the process of screening or outputting, this kind of compressed format may not support the phenomenon, which is a problem with the output.

7. How are the image reproduction effects of changing tone?

We can use the image adjustment function of related software as much as possible to modify the image to suit the printing effect. However, to a general extent, the quality of the original document directly determines the quality of the output.

8. How does the line look?

For line art, the most basic quality factor is the density and border definition. This directly affects its quality in copy transfer. Also, be aware that the resolution of linework and text as images must not be lower than 600dpi.

9. Is the image sharp enough?

Scanners and various digitizing devices have the effect of softening the image during image processing. Therefore, the processed image undergoes a sharpening process. The sharpening effect is not so easy to see on the screen. Therefore, it is necessary to conduct trials for a period of time to find out the laws. There is a general method: the image is magnified twice as much on the screen, and then after sharpening, it is observed whether the border outline of the image has a hard edge effect. If the hard-edged effect happens, it is generally considered that the definition of the emphasis is appropriate.

10. Other considerations and considerations

The larger the dynamic density range of the scan, the more detail that can be captured. So when scanning images, pay attention to the choice of scanner.

If you do not find a scanner of good quality or you are not sure about the quality of the processed image, it is best to send the job to a specialized printing service center for processing.

When selecting a device for storing images, compatibility with the computer system must be guaranteed.

If you have a color management system, correct the scanning equipment, screen, and proofing equipment before starting work.

Source: HC Network