How do fiber optic sensors identify color?

Fiber optic sensors rely on optical principles to detect object properties such as reflection and scattering. They can identify color based on the wavelength characteristics of reflected light. The Atonm technical editor explains how fiber optic sensors detect color.

1. Working principle

Fiber optic sensors consist of a light source, optical fiber, and photodetector. Light from the source is transmitted to the object surface, then reflected or scattered back through the fiber to the detector and converted to an electrical signal. Different surfaces reflect different wavelengths, enabling color detection.

2. Color detection principle

Color detection uses wavelength differences: shorter wavelengths appear bluer, longer wavelengths redder. By measuring reflected light across wavelengths, the sensor determines the object color. Many systems use the RGB color space (Red, Green, Blue), measuring intensity in each channel (0–255) to identify color.

3. Detection techniques

Common methods include comparison and triangulation.

Comparison method

The simplest approach compares an object's color to preset reference colors. It is easy to use but sensitive to ambient light and requires reference presets.

Triangulation method

A more accurate technique measures reflected intensity in red, green, and blue bands, converts them to color coordinates, and computes the color position. This method needs three light sources (e.g., red, green, blue) and yields higher precision and adaptability.

4. Use color sensors

For many color detection tasks, a Color Sensor is a practical choice. Atonm Color Sensors offer high precision and fast response and are widely used in automation and robotics.

Atonm's Color Sensor supports triple 16‑bit RGB processing and can detect nearly 3000 colors with fine color discrimination. It uses an 8‑channel output and multiple dedicated probes to meet different size and distance requirements.