Agricultural Inspection

Agricultural Food Product Sorting and Inspection Systems

Moisture is a key indicator of process control and quality in agriculture, textile processing, and the forest-product industry. Because water is opaque to SWIR illumination, detecting its presence or absence can be useful in gauging crop health and product ripeness or dryness.

Gauging the relative moisture content of leaves helps assess crop health and quality.  By selectively imaging at the wavelengths of strongest absorbance for water, items with higher water composition will appear darker than drier tissues.

The bottom portion of the ear on the right is much darker in the area that the visible image shows damage, indicating a pooling of moisture characteristic of bruising.  Such bruises can be seen under the skin of fruits that are passing by on an inspection line while they are invisible to the eye. Though perfectly suitable for many processed foods, bruises are not acceptable in fresh produce for retail purchase. The SWIR camera permits sorting high value produce away from the lower grade fruit prior to processing.

In textile processing, moisture detecting SWIR imagers are useful in the dyeing process. In particleboard manufacturing, online SWIR-based machine vision systems measure moisture in chips, and the collected data is used to regulate heating and drying operations downstream.