1. Light Source: Scanners use a light source to illuminate the document or object being scanned. The light source can be a fluorescent lamp, LED, or laser, depending on the type of scanner. This light illuminates the document and allows the scanner to capture the image.
2. Optics: After illumination, the light is directed through a series of lenses and mirrors that focus the light onto the surface of the document. These optics ensure that the image is properly focused and captured with accuracy.
3. Scanning Sensor: The scanning sensor is a critical component of a scanner. There are two main types of sensors used in scanners: CCD (Charge-Coupled Device) and CIS (Contact Image Sensor).
CCD Sensor: CCD sensors use a complex arrangement of tiny light-sensitive cells to capture the image. They provide high-quality scans with accurate color reproduction, making them suitable for professional and archival purposes.
CIS Sensor: CIS sensors are more compact and energy-efficient. They use a linear array of sensors to capture the image in a single pass. While they may not offer the same level of image quality as CCD sensors, they are commonly used in portable and office scanners due to their convenience and speed.
4. Analog to Digital Conversion: As the light is reflected off the document’s surface, the scanning sensor detects variations in light intensity. These variations represent different colors and shades. The analog signal generated by the sensor is converted into a digital signal through an analog-to-digital converter (ADC).
5. Image Processing: Once the analog signal is converted into a digital format, image processing algorithms are applied to enhance the quality of the scanned image. These algorithms correct color balance, remove noise, and adjust contrast to ensure the final image accurately represents the original document.
6. Resolution: Scanners capture images at a specific resolution, usually measured in dots per inch (DPI). Higher resolutions result in more detailed images but also larger file sizes. Scanner resolution determines the level of detail and sharpness in the scanned image.
7. Color Depth: Color depth, measured in bits per pixel, determines the range of colors that can be captured. Common color depths are 24-bit (8 bits per channel for red, green, and blue) and 48-bit (16 bits per channel), allowing for a wider range of colors and more accurate color reproduction.
8. Output and Connectivity: The scanned image is processed and sent to the connected computer or device. Scanners can use various connectivity options, such as USB, Wi-Fi, or Ethernet, to transfer the scanned data to the host device.