US 4,801,804 AGranted

Method and apparatus for near infrared reflectance measurement of non-homogeneous materials

AssigneeTrebor Industries, Inc.

InventorRobert D. Rosenthal

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Abstract

A method and apparatus for near infrared reflectance measurement of non-homogeneous materials. Constituents of a material are quantitatively analyzed by reflectance techniques utilizing a planar surface of the material within a cup-shaped sample holder opaque to near-infrared radiation. A predetermined area of the planar surface is uniformly irradiated with near infrared radiation emitted from a source spaced a predetermined distance away from the planar surface. Near infrared radiation reflected by substantially all of the predetermined surface area is detected with a near infrared radiation detector spaced a predetermined distance away from the planar surface, to provide a signal which is processed to measure an average content of a constituent in the sample material. The source and detector are contained in a probe which is calibrated by inserting the probe into a cavity. The probe is spaced from the bottom of the cavity such that the cavity reflectance is about equal to that of the material for which the probe is being calibrated.

Claims10

Dependent claims

A method for near infrared reflectance measurement of a constituent of a sample material utilizing a near infrared interactance quantitative analysis device, comprising:

(a) providing sample material having a constituent to be measured within a near infrared-opaque cahbmer with the sample material having a substantially planar surface;
(b) uniformly irradiating a pedetermined surface area of the planar surface of the sample material with substantially uniform, highly diffuse, multiple-wavelength near infrared radiation for uqantitative measurement of a sample constituent, which radiation is emitted from a multiple- wavelength near infrared radiation source spaced a predetermined distance away from the planar surface for uniformly irradiating said predetermined surface area;
(c) detecting near infrared radiation reflected by substantially all of said predetermined surface area with a near infrared radiation detector spaced a predetermined distance away from the planar surface of the sample material to detect near infrared radiation reflected by substantially all of said predetermined surface area, the predetermined surface area being sized to reflect near infrared radiaion from said source to said detector which is indicative of an average content of said consituent of said sample material, said detector providing an electrical signal upon detection of near infrared radiation, said detector being positioned so as to prevent near infrared radiation emitted from said source from directly impinging on said detector;
and
(d) processing an electrical signal provided by said detector to quantitatively measure an average content of said constituent for said sample material.

2 more elements

An apparatus fro measuring a constituent of a sample material, comprising:

(a) a sample holder having a chamber for containing a sample material having a cosntituent to be measured, the sample holder being formed of near infrared-opaque material;
(b) means for forming a substantially planar surface of the sample material within the chamber;
(c) a source of highly diffuse, multiple-wavelength near infrared radiation for quantitative measurement of a sample constituent, said source being spaced a predetermined distance away from the planar surface of the sample material so as to irradiate a predetermined surface area of the planar surface with substantially uniform, highly diffuse, multiple-wavelength near infrared radiation;
(d) a near infrared radiation detector spaced a predetermined distance away from the planar surface of the sample material in position to detect near infrared radiation reflected by substantially all of said predetermined surface area, said predetermined surface area being sized to reflect near infrared radiation from said source to said detector which is indicative of an average content of said constituent of said sample material, said detector providing an electrical signal upon detction of near infrared radiation;
(e) means for preventing near infrared radiation emitted from said source from directly impinging on said detector;
(f) means for processing an electrical signal provided by said detector to quantitiatively measure an average content of said constituent for said sample material.

3 more elements

Dependencies are inferred from the claim text.