Standard Shortwave Infrared Camera Specs for Cotton Contamination Sorters
Shortwave infrared sorters use dual-band InGaAs line scan cameras to detect synthetic polymers in cotton by targeting carbon-hydrogen absorption peaks.
Reflectance Spectrum
Analytical Output
A graphic representation of light reflected from a surface across different wavelengths characterizes the precise colour profile of a textile. Technicians analyze the reflectance spectrum of a dyed fabric to determine its colour strength and shade consistency. This output is generated by a spectrophotometer and provides the primary data source for digital colour matching.
System Mechanism
The spectrophotometer projects light across the visible spectrum from 380 to 720 nanometres onto the fabric sample. The surface absorbs certain wavelengths depending on the dye molecules present and reflects the remaining light to a sensor. Plotting these reflection levels produces the reflectance spectrum, where a lower reflectance value at a specific wavelength corresponds to higher dye concentration in the fabric.
This curve remains constant for a specific dye combination and substrate, providing an objective footprint of the fabric shade.
Operational Control
Calibrating the spectrophotometer with standard black and white tiles is necessary before measuring the sample. To obtain a reliable reflectance spectrum, the operator folds the fabric multiple times to prevent background light from leaking through. Taking multiple measurements at different points of the fabric roll helps calculate an average shade profile.
Technicians compare this curve against the master standard to calculate the colour difference value.
Process Constraint
This analysis can be skewed by surface texture, yarn lustre or the presence of optical brighteners in the fabric. Structured fabrics like corduroy require specialized viewing geometries to minimize surface reflection errors.