X-rite Gmbh

Patrick S Rood

Bernard J Berg

Jon Nisper

Thomas Richardson

Brett Allen Pawlanta

Brian Dale Teunis

Mark A Cargill

Thomas J Boes

Brett A Pawlanta

Brian Teunis

Jon K Nisper

Jon Kenneth Nisper

An apparatus for measuring a spatially under-sampled Bidirectional Reflectance Distribution Function (BRDF) of a surface. The apparatus may comprise a first light source directed to illuminate the surface from a first illumination direction, and a plurality of sensors positioned to receive light reflected by the surface. The plurality of sensors may comprise first, second and third sensors positioned to receive light reflected by the surface in first, second and third non-coplanar directions. In various embodiments, the apparatus may also comprise a computer in communication with the plurality of sensors. The computer is configured to convert light sensed by the plurality of sensors into a first appearance property of the surface considering the first, second, and third reflectance directions.

Measuring an appearance property of a surface using a bidirectional reflectance distribution function

Measuring an appearance property of a surface using a spatially under-sampled bidirectional reflectance distribution function

To provide a standard for determining an objective level of performance of photographic film developer processes, a production sensitometer, of the type commonly used in the field, is correlated with a high precision, master sensitometer, defined as a standard. Relative exposure values are computed for each step of a step wedge exposed by a production sensitometer with reference to a corresponding step of a step wedge exposed in the master sensitometer. The relative exposure values are recorded and stored in a read-only memory in the production sensitometer. In the field, the steps of a step wedge on a test film strip exposed by the production sensitometer and developed by the developer processor to be tested, are read by a densitometer which uses the stored relative exposure values to compute density values for the test strip correlated to the master sensitometer. The developer processor may then be adjusted such that the developed film will match quality control parameters, e.g. speed index, contrast index, etc., supplied by the film supplier.

Apparatus for use in optimizing photographic film developer apparatus

A portable spectrophotometer includes a small-diameter optical sphere as well as optical detectors and signal processing and display circuitry which allows the instrument to be taken to an object to be measured and which provides a readout of color values at the portable instrument. The instrument is capable of providing specular-included and specular-excluded color readings simultaneously. The interior of the integrating sphere is coated with a highly reflective, color-absorbing material, and light from an incandescent lamp is diffused within the sphere prior to reaching the object to be measured. The sphere is provided with a first aperture which receives spectrally-included light and which is positioned to absorb a spectral component of the diffused source light. A second aperture positioned at a corresponding angular position with respect to the object measures specular-excluded light, excluding the specular component absorbed by the first aperture. Light detected from the first aperture is analyzed at a plurality of wavelengths obtained by the use of interference filters, and the light obtained from the second aperture is analyzed at one of the plurality of wavelengths. By appropriately combining the specular-included and specular-excluded at one wavelength, a value for the specular component is derived. Since this value is a theoretical constant, it is used to derive a specular-excluded reading from each of the specular-included readings at the different wavelengths.

Portable spectrophotometer

Growing community of inventors

Walker, MI, United States of America

Patrick S Rood