The working principle of optical imaging scanners is based on photoelectric conversion technology, and the main process is as follows:
Light source illumination: After the scanner is started, the light source (such as LED array or cold cathode fluorescent tube) emits light and illuminates the document or image to be scanned. Optical imaging scanners collect optical signals of objects through an optical system, convert them into electrical signals, and then digitally process them to generate storable and transportable digital images. Different types of scanners optimize the optical acquisition and signal conversion process according to application scenarios
Light reflection/transmission: For opaque objects such as photos and ordinary documents, light is reflected by the surface; For transparent media such as slides and negatives, light passes through the original.
Optical path guidance: The reflected or transmitted light is accurately guided and focused through an optical lens group (reflector).
Photoelectric conversion: The focused light is projected onto a photosensitive element (such as CCD or CIS) to convert the optical signal into an electrical signal (analog voltage).
Analog to digital conversion: An analog-to-digital converter (ADC) converts an analog signal into a digital signal (discrete 0s and 1s), which determines the color depth and grayscale level of the scanned image.
Image processing: Digital signals are sent to an image processor or computer driver software for processing, including color correction, gamma correction, mesh removal, sharpening, and other operations, and then saved in a specific file format.
Data transmission: The processed digital image data is transmitted to a computer or other device through an interface.
performance metrics
Optical resolution: Refers to the number of pixels in the horizontal and vertical lines, indicating how many points can be resolved per inch, which depends on the number of CCDs and the quality of the lens. The higher the optical resolution, the clearer the details of the scanned image.
Color Bit Number: Indicates the color detection capability of a pixel, represented by the data bits of color on each pixel. Common specifications include 18 bit, 24 bit, 30 bit, 36 bit, 42 bit, and 48 bit. The more color bits there are, the more realistic the color reproduction of the scanned image will be.
Dynamic range: reflects the ability to reproduce color tone levels and describes the scanner's ability to reproduce subtle changes in color tones. The wider the dynamic range, the stronger the sense of hierarchy in the scanned image.
Scanning speed: refers to the number of pages or data that a scanner can scan in a unit of time. The faster the scanning speed, the higher the work efficiency.
Interface type: affects the connection method and data transmission speed between the scanner and the computer or other devices. Common interface types include USB, Ethernet, Wi Fi, etc.