How to use Scanners and techniques

　　How to use Scanners and techniques

Many users in the purchase of scanners, often found that the quality of scanned pictures is not ideal, in fact, this situation, the main or the user with the skills of the scanner is closely related.

　　Prepare to do the work well

It is necessary for ordinary users to have a rudimentary understanding of the fundamentals of the scanner before they can use the scanner, which will greatly assist in using the scanner correctly and reasonably. The way the scanner gets the image is by lighting the light to a picture or document to be scanned, which is reflected by the photosensitive element--CCD (Charge coupled Device, charge-coupled Element) or CIS (contact image Sensor), because the color of the image varies, The intensity of the reflected light is also different, the photosensitive element can receive various intensity of light, and converted to binary digital signal, and finally by the control scanning software to restore the data to the display can see the image.

In order to reflect the image objectively and truthfully, it is necessary to ensure that the light can be smoothly reflected on the manuscript to be scanned, the author suggests that you can first turn on the scanner before scanning to preheat for 5-10 minutes, so that the lamp in the machine to achieve uniform light-emitting State, so as to ensure that the light on average In addition, do not because the scanner tilt or jitter affect the scanning quality, users should try to find a relatively flat, stable place, some users to save office space and directly put the scanner above the chassis of the practice of absolutely not take. Now, Canon company's N series scanners have achieved a vertical scan, equipped with a dedicated scanner stent, effectively saving office space. In addition, before scanning carefully check whether there is a stain on the top of the glass, if there must be a soft cloth to wipe clean, so as not to affect the scanning effect.

　　Pre-sweep steps must be minimal

In order to save scanning time, some users covet convenience, often ignoring the advance sweep steps. In fact, before the official scan, pre-sweep function is very necessary, it is to ensure that the scanning effect of the first hurdle. There are two benefits to the pre sweep, one is the image after the pre-sweep we can directly determine the area that we need strokes, to reduce the processing of the image after scanning, the second is through the observation of the image after the pre-scan, we can generally see the color of the image, effect, etc., such as not satisfied with the scan parameters can be reset, After the adjustment, scan again.

Limited to the working principle of the scanner, the image scanned can more or less distort or distort. Therefore, a good manuscript to get high-quality scanning effect is particularly important, and poor quality of the manuscript, even through software processing can improve the scanning effect, but it is the practice of the mend. As for those who defaced serious images, no matter how the processing can not get the desired effect, therefore, we must try to use the best quality manuscript scanning. For some smaller sections, should be placed in the center of the scanner, so as to reduce the production of deformation.

　　How much resolution to use

Many users often have questions about how much resolution scans are used when using scanners. In fact, this has to be determined by the user's actual application requirements. Higher resolution means more image details, clearer effects, and more perfect color reduction, but it also means that the scanned image file is enlarged and difficult to handle. For more Internet applications, the resolution of pictures on the Web site is usually around 75dpi, which means that scanning with a 100dpi resolution is more than sufficient, and the resolution for printing is generally 300 to 400dpi, so you want to print the artwork by scanning, At least 300dpi more than the resolution, of course, if you can use 600dpi is better. If you want to print the scanned artwork through the printer, you must consider the resolution of the printer to decide. According to the actual experience, a printer with a resolution of 1440dpi, just scan the image at 360dpi resolution to get a good print effect. This is because the printer and the scanner work and the meaning of the resolution is completely different.

　　Wide application of OCR

I believe many friends buy a scanner for most purposes is to reduce the text input workload, improve work efficiency. As a result, OCR is one of the most commonly used features of scanners. It is convenient and effective to recognize the Chinese characters and English in the scanned documents by software. Therefore, in addition to mastering the correct scanning methods, the selection of appropriate OCR software is also extremely important. Most commonly used OCR software is bundled with the scanner sales, such as Canon Scanner Rosettastone, OmniPage and so on. Although OCR software can recognize Chinese characters automatically, it requires many application techniques to achieve high efficiency and accuracy.

First, you need to scan the document in black and white mode, but also note that the threshold value (threshold, which indicates a range of parameters, greater than or less than this range does not produce an effect), which determines the extent to which black can be viewed by the scanner as a black dot, This can easily distinguish the black of the text and background interference, if properly adjusted, can speed up the scanning speed. This value adjustment can be in the scanned image of the tonal value (tone value) statistical histogram (histogram), first distinguish between two or more peaks, and then adjust the threshold between the two, you can find a good distinction between the results of the position. If you think this approach is more cumbersome, there is another handy way to determine the resolution by the size of the text. In general, a 200 or 300dpi resolution can have a fairly good effect. If the text to be scanned is smaller than the newspaper text, you can improve the resolution, so that you can enlarge the scanning document and enhance the recognition rate.

When users need to scan the larger thickness of the magazine, if the direct scan, it will inevitably occur within the text due to the inability to fully spread out some of the text is not clear and distorted distortion of the situation, such a result is OCR software can not correctly identify, greatly reduce the recognition rate. What do we do? Users may wish to split the book into a single sheet of pages before scanning. For the general newspaper, because itself is a leaflet form, so there is no such problem, but because the newspaper area is usually large, not a scan, so the pre-sweep in advance box Scan range, one scan a region, such recognition effect will be greatly improved.

　　Transmission drafts and other printed materials

In addition to scanning ordinary reflection, users sometimes need to scan the transmission manuscript. Transmission draft includes slides (positive), negative two kinds. Because the general scanner is designed for reflective scans, it is recommended that you use a film scanner with a special film scanning feature when scanning transmission drafts.