Fruit Inspection Using a Liquid Crystal Tunable Optical Filter Multispectral Camera

Currently, fruit is sorted for bruises and blemishes by hand. This is an inefficient and labor intensive method for detemining fruit quality, in need of automation. It has recently been determined that visible and near infrared multispectral imaging is useful for extracting several fruit quality characteristics. In order to acquire information in several bands as fruit is processed, a high throughput high-speed tunable optical filter is required. While acousto-optic filters are adequately fast tuning, image quality is poor, clear apertures are small, and image registration is not maintained. BNS proposes a ferroelectric liquid crystal tunable optical filter which combines speed comparable to acousto-optic filters, with large clear apertures, large acceptance angles, and excellent image quality. This device, used with a single CCD camera, provides a wealth of information, not attainable using visual inspection, in a non-intrusive manner.