Color Sensors with Extended LCh Color Space

With the integration of the LCh color space, Micro-Epsilon expands the application range of the colorSENSOR CFO250 series and improves color recognition accuracy in industrial inline measurements by around ten percent compared with the previously used Lab* color space.

Higher color accuracy for dynamic inline measurements
Controllers in the colorSENSOR CFO250 series are primarily used in applications that require very high measurement speeds and reproducible color detection. With measurement rates of up to 30 kHz, they are suitable for highly dynamic inline processes such as 100% quality control in print mark detection, batch inspection and similar applications.

Until now, the CFO250 supported the XYZ, xyY, Lab*, Luv* and u’v’L* color spaces. With the addition of the LCh color space, the correspondence between measured colors and human visual perception is further improved. In combination with segment tolerance, this results in approximately ten percent higher perceptual agreement compared with the Lab* color space, which is particularly relevant for demanding color differentiation tasks.

Structure and benefits of the LCh color space
The LCh color space consists of three components: luminance (L), chroma (C) and hue (h). L represents brightness on a scale from 0 (black) to 100 (white), C describes color saturation from low to high, and h defines the hue as an angle from 0° to 360°. This structure allows hue and saturation to be adjusted independently of brightness.

Thanks to this separation, the LCh color space is especially well suited for intuitive visualization and editing of colors. At the same time, it enables more precise evaluation of color deviations, as changes in hue, saturation or brightness can be assessed individually.

Fast evaluation and flexible data interfaces
The colorSENSOR CFO250 compares taught reference colors with current measurement values quickly and reliably, classifying them as OK or NOK. In addition, raw data can be transmitted at up to 500 Hz via UDP, RS232 or USB interfaces directly to a PLC or machine control system. Edge or level triggers determine how long or how many measurement values are output.

Large color memory and robust design
For applications with frequent product or batch changes, the CFO250 offers a large internal color memory. Up to 254 color groups with more than 320 individual colors can be stored in the controller. These color groups help to further increase detection accuracy and ensure reliable differentiation between color variants.

The robust aluminum housing with IP65 protection rating enables operation in harsh industrial environments. Commissioning, calibration and color teaching are carried out via an intuitive web-based interface, reducing integration effort in existing production systems.

Context
By adding support for the LCh color space, Micro-Epsilon positions the colorSENSOR CFO250 series for applications that demand maximum color accuracy, high dynamics and reproducible results. The combination of fast signal processing, flexible data access and improved colorimetric evaluation supports data-driven quality control processes in modern production lines.

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