Principles and Applications of Color/Color-recognition/Mark Sensors

Although the human eye can distinguish colors well, people may describe the same color differently, making verbal descriptions inadequate for precise color detection and control. Using fully calibrated color sensing devices provides a digital description of color. Devices range from expensive laboratory spectrometers to economical RGB color recognition sensors (such as Atonm's color/mark sensors).

Before explaining how electronic devices recognize color, it helps to understand human color perception. Color results from interaction of light, object and observer. Reflected light depends on object composition; e.g., red paper absorbs green and blue wavelengths while reflecting red, appearing red to the observer. Both the object and light source affect perceived color.

Color/mark sensors convert light to analog voltage or digital signals. The analog path includes photodiode arrays and integrated current-to-voltage converters (transimpedance amplifiers). R.G.B sensors measure reflected proportions of red, green and blue to detect color; this method is accurate for distinguishing similar colors.

RGB sensors commonly have three light sources (red, green, blue). Light reflects from the target through the same optics; reflection or absorption depends on object color.

RGB sensors offer two measurement modes: 1) analyze ratios of red/green/blue light — these ratios remain stable despite distance variations; 2) measure absolute reflected intensities to detect subtle color differences, though this mode is more sensitive to positioning. Many RGB sensors include onboard graphs and thresholds to simplify setup.

Atonm (Guangzhou) Intelligent Technology Co., Ltd. develops, manufactures and sells industry-specific controllers and sensors (color/mark sensors).

CL1 Smart Digital Series Color Sensor automixes light sources to generate stable detection illumination; offers microsecond-level response and multiple sensing head options; features intelligent digital sensitivity settings and multi-digit display for clear visualization.

Color/mark sensors apply to packaging, lithium battery, food, pharmaceutical, automotive, hardware, inkjet printing, screen printing, die-cutting, bag making and zipper machinery for detecting colors on solids and liquids.