First of all, we need to know what is called the resolution of the scanner. All types of scanners are labeled with its optical resolution and maximum resolution. Barcode scanner resolution in dpi, dpi is the abbreviation of the English Dot Per Inch, meaning the number of pixels per inch. After understanding the meaning of the resolution of the scanner, let's see how important these scanner parameters are for us.
Optical resolution refers to the actual amount of information that can be captured by the optical system of the barcode reader, that is, the resolution of the reader's photoreceptor. For example, the maximum scanning range of 216mm × 297mm (suitable for A4 paper) reader can scan the maximum width of 8.5 inches (216mm), its photoreceptor original contains 5100 units, its optical resolution of 5100 points ÷ 8.5 inches = 600dpi. common optical resolution of 300 × 600dpi, 600 × 1200dpi, 1200×2400dpi or higher.
Reader color resolution, also known as color depth, color mode, color bits or color gradation, in short, are expressed in the scanner to distinguish color or grayscale fine degree of the index, it is the unit is bit (bit). The exact meaning of the color bit is how many "bits" to indicate the scanning of a pixel. For example: 1bit can only represent the black and white pixels, because the numbers in the computer using binary, 1bit can only represent two values (2 1 = 2) that is, 0 and 1, which represent black and white; 8bit can represent 256 gray levels (2 8 = 256), which represent the different gray levels from black to white; 24bit can represent 16777216 kinds of colors (2 24=), which represent the different gray levels from black to white; 24bit can represent 16777216 kinds of colors (2 24 = 16777216), which can represent the different gray levels of black to white; 24bit can represent 16777216 kinds of colors (2 24 = 16777216), which can represent the different colors of black to white. 16777216), generally referred to as more than 24bit color for true color, of course, there are 30bit, 36bit, 42bit machine types. Theoretically, the more color bits a barcode scanner has, the more realistic the color will be.
Let's talk about the relationship between barcode scanner resolution and file size. General scanning applications can automatically calculate the file size when you preview the original manuscript samples, but understanding how the file size is calculated is more helpful in managing your scanned files and determining the appropriate choice of scanning resolution. The formula for black and white image files is: horizontal size × vertical size × (scanning resolution) 2 ÷ 8. The formula for color image files is: horizontal size × vertical size × (scanning resolution) 2 × color depth × 1/8. For example, scanning a normal color photo (3.5 × 5 inches) in 24-bit color RGB, with a scanning resolution of 300 dpi, the length of the image file is 5 × 3.5 × 300 dpi. 5 × 3.5 × 300 2 × 24 × 1/8 = 4725000Byte that is, 4.7MB.
The last concept that needs to be elaborated is OCR, which is the abbreviation of English Optical character recognition. Its function is to read the text image information on printed materials through optical input devices such as barcode scanners, and use pattern recognition algorithms to analyze the morphological features of the text so as to identify different Chinese characters. Chinese OCR is generally only suitable for recognizing printed Chinese characters. The use of scanners plus OCR can partially replace the keyboard to enter the function of Chinese characters, is a labor-saving and fast text input method. The common OCR are Tsinghua Wentong, Shangshu, Monty Python and so on.
Types of barcode scanners:
Scanners and other types of many common types:
A handheld barcode scanner (of course, some people call handheld barcode scanner gun or barcode reader). Handheld scanner (barcode scanner gun) is a technology introduced in 1987 to form the product, the shape is very much like a supermarket cashier held in the hands of the use of scanners. The vast majority of hand-held scanner gun using CIS technology, reader optical resolution of 200dpi, black and white, grayscale, color a variety of types, of which the color type is generally 18-bit color. There are also individual high-grade products using CCD as a photoreceptor, can be achieved bit true color, scanning effect is better.
Second, a small drum scanner (of course, there are people called small drum scanner gun reader). This is a hand-held scanner and platform scanner intermediate products (in recent years there are new appearances, because it is built-in power supply and small size is known as the notebook scanner) the vast majority of such products using CIS technology, optical resolution of 300dpi, color and grayscale two kinds of color models are generally 24-bit color. There are also and a few small drum barcode scanner using CCD technology, the scanning effect of the reader is significantly better than the CIS technology products, but due to structural limitations, the reader volume is generally significantly larger than the CIS technology products. Small drum type design is the scanner lens is fixed, and move the object to be scanned through the lens to scan, operate like a printer, the object to be scanned must be sent through the machine again, therefore, the object to be scanned can not be too thick. The biggest advantage of this scanner is that the volume is very small, but because of the use of a variety of limitations, such as only thin paper scanning, the range can not exceed the size of the scanner.
Third, the platform scanner. Also known as flatbed reader, desktop scanner gun, currently on the market most of the scanner belongs to the flatbed barcode scanner, is now the mainstream. This type of scanner optical resolution between 300dpi-8000dpi, reader color bits from 24 to 48 bits, reader scanning format is generally A4 or A3. flatbed benefits like the use of photocopiers, as long as the barcode scanner gun open the top cover, no matter what is a book, newspaper, magazines, photo negatives can be put on the scan, quite convenient, and barcode scanner gun The scanning effect is also the best of all common types of scanners.
Other large-format scanning with a large-format scanner, pen scanner, film scanner (note that not a flatbed scanner plus scanning, the effect is much better, of course, the price is expensive), physical scanning gun (not a physical scanning capability of the flatbed scanner, a bit similar to a digital camera), and is mainly used in the field of industry printing and layout of the cylinder scanner, and so on a lot.
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