Patent ID: 6504154
Filing Date: 2003-01-07
Classification: G01N

Abstract:
A non-destructive sugar content measuring apparatus comprising a plurality of trays on which vegetables and fruits are to be placed, a transport means for successively delivering the trays at appropriate intervals, and first, second and third measuring sections provided in the course of a transport path and at which laser beams having wavelengths &lgr;1, &lgr;2 and &lgr;3 are respectively made incident on each vegetable or fruit and the amount of light of each laser beam emergent from the vegetable or fruit is measured with a detector provided at each measuring section and at the same time the absorbance of each laser beam is determined from the amount of incident light made incident on the vegetable or fruit and the amount of detected light which has been measured with the detector, to measure the sugar content of the vegetables and fruits on the basis of each absorbance thus determined wherein;the wavelengths &lgr;1, &lgr;2 and &lgr;3 of said laser beams satisfy the conditions of: 860 nm&lE;wavelength &lgr;1<900 nm, 900 nm&lE;wavelength &lgr;2&lE;920 nm, 920 nmand, where standard deviations of wavelength variations in the wavelengths &lgr;1, &lgr;2 and &lgr;3 are represented by &Dgr;&lgr;1, &Dgr;&lgr;2 and &Dgr;&lgr;3, respectively, satisfy the condition of the following mathematical expression (1):[f1(&lgr;1)Ã—&Dgr;&lgr;1+f2(&lgr;2)Ã—&Dgr;&lgr;2+f3(&lgr;3)Ã—&Dgr;&lgr;3]<0.5 brixâ€ƒâ€ƒ(1); in which mathematical expression (1), f1(&lgr;1), f2(&lgr;2) and f3(&lgr;3) respectively represent sugar content variation functions (brix/nm) determined from sugar content variation curves showing the relationship between the wavelength variations in the wavelengths &lgr;1, &lgr;2 and &lgr;3 and the sugar content variations that accompany the former.