SPECIMEN MEASURING DEVICE AND COMPUTER PROGRAM PRODUCT

• US 20160040985A1
• Filed: 08/03/2015
• Published: 02/11/2016
• Est. Priority Date: 08/05/2014
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: NAGAI, Sho, Masuda, Kensuke, Maruyama, Go, Yamanaka, Yuji, Kamijo, Naohiro, Kagitani, Kenji
• Granted Patent: US 9,958,265 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 11/303 using photoelectric detection means
• CPC Class Codes: G01B 11/306 for measuring evenness
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/14 using refracting elements, e.g. prisms G01J3/18, G01J3/26 take precedence prisms per se G02B5/04
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/465 taking into account the colour perception of the eye; using tristimulus detection
• CPC Class Codes: G01J 3/504 Goniometric colour measurements, for example measurements of metallic or flake based paints
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01N 2021/1776 Colour camera
• CPC Class Codes: G01N 2021/3177 Use of spatially separated filters in simultaneous way
• CPC Class Codes: G01N 2021/4711 Multiangle measurement
• CPC Class Codes: G01N 2021/575 Photogoniometering
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: G01N 21/4785 Standardising light scatter apparatus; Standards therefor
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/57 Measuring gloss
• CPC Class Codes: G01N 21/8422 Investigating thin films, e.g. matrix isolation method
• CPC Class Codes: G01N 2201/0635 : Structured illumination, e.g. with grating

Abstract

A specimen measuring device includes: a light source device that irradiates a specimen surface of a specimen with illumination light from multiple illumination units at a plurality of illumination angles; a spectral camera device that is arranged above the specimen surface, spectrally separates reflected light from the specimen surface, and acquires 2D spectral information through a single image capturing operation; and a calculating unit that calculates deflection angle spectral information of the specimen surface used to measure a measurement value of a certain evaluation item of the specimen using a change in an optical geometrical condition of an illumination direction and an image capturing direction between pixels in an X axis direction and a Y axis direction of the spectral information.

Claims

1. A specimen measuring device comprising:

a light source device that irradiates a specimen surface of a specimen with illumination light from multiple illumination units at a plurality of illumination angles;

a spectral camera device that is arranged above the specimen surface, spectrally separates reflected light from the specimen surface, and acquires 2D spectral information through a single image capturing operation; and

a calculating unit that calculates deflection angle spectral information of the specimen surface used to measure a measurement value of a certain evaluation item of the specimen using a change in an optical geometrical condition of an illumination direction and an image capturing direction between pixels in an X axis direction and a Y axis direction of the spectral information.

2. The specimen measuring device according to claim 1,

wherein the optical geometrical condition is at least one of a measurement range of the specimen surface, an angle of view of the spectral unit, a distance between the specimen surface and the illumination unit, a distance between the spectral unit and the illumination unit, and an illumination angle of the illumination unit, and

the illumination unit and the spectral unit are arranged such that a deflection angle range to be measured is continuously acquired in the optical geometrical condition.

3. The specimen measuring device according to claim 1,

wherein the calculating unit calculates a brightness histogram for each illumination angle and each spectral wavelength using the 2D spectral information acquired by the spectral camera device, and calculates a glittering area and glittering strength of each illumination angle and each spectral wavelength.

4. The specimen measuring device according to claim 1,

wherein the light source device changes at least one of a light quantity and an exposure time at a time of image capturing, and

the spectral camera device synthesizes a plurality of pieces of 2D spectral information acquired according to a change in a light quantity, an exposure time at a time of image capturing, or a light quantity and an exposure time at a time of image capturing by the light source device, and generates the 2D spectral information having an enlarged dynamic range.

5. The specimen measuring device according to claim 1,

wherein the calculating unit determines a range of a diffusion light reflection angle excluding a regular reflection angle based on the 2D spectral information acquired by the spectral camera device, reconstructs an image using only pixels determined to be diffusion light other than regular-reflected light of an illumination of a particle image of each illumination angle, and calculates uniformity of an area of a bright portion and a dark portion as a graininess based on the reconstructed image using an entropy, variance or Fourier analysis of an image.

6. The specimen measuring device according to claim 1, wherein the calculating unit calculates a gloss value from a regular reflection angle, and calculates a haze value from the regular reflection angle and an adjacent angle using the deflection angle spectral information.

7. The specimen measuring device according to claim 1, further comprising,

a projector that projects slit light of a certain pattern in an image capturing range of the spectral camera device,

wherein the calculating unit measures measurement values of an image clarity and an orange peel of the specimen using the deflection angle spectral information generated by capturing an image of the slit light through the spectral camera device.

8. The specimen measuring device according to claim 1, further comprising,

a three-dimensional (3D) information acquiring device that measures and acquires 3D shape information of the specimen surface of the specimen,

wherein the calculating unit calculates a normal line direction of each position of the specimen surface using the acquired 3D shape information of the specimen surface, and corrects the deflection angle spectral information acquired by the spectral camera device using the calculated normal line direction.

9. The specimen measuring device according to claim 1,

wherein the calculating unit calculates measurement values of deflection angle color information, BRDF information, a glittering feeling, a graininess, a gloss, a haze, image clarity, and orange peel using the deflection angle spectral information.

10. The specimen measuring device according to claim 7,

wherein the projector projects an image of a white noise in the image capturing rage of the spectral camera device, and

the calculating unit calculates the measurement value of the image clarity of the specimen using the deflection angle spectral information obtained by capturing an image of the white noise through the spectral camera device.

11. The specimen measuring device according to claim 1,

wherein the spectral camera device is a multi-band camera that that includes a main lens, a group of spectral filters, and a micro lens, and acquires spectral information according to number of the spectral filters, or a hyper spectral camera that includes one or more sets of filters and diffraction gratings or prisms, and

the spectral camera device acquires the 2D spectral information in synchronization with irradiation of illumination light of each illumination angle of the illumination unit through a single image capturing operation.

12. The specimen measuring device according to claim 11,

wherein the multi-band camera includes the group of spectral filters inserted into the main lens and a micro lens array inserted between the main lens and a light receiving element, and acquires the spectral information according to the number of the spectral filters through each micro lens of the micro lens array.

13. The specimen measuring device according to claim 12,

wherein the multi-band camera acquires the spectral information according to the number of the spectral filters as the group of the spectral filters is installed between the micro lens array and the light receiving element.

14. The specimen measuring device according to claim 1,

wherein the spectral camera device has an optical configuration in which a resolution of each pixel for the specimen is 10 μ

m to 100 μ

m.

15. A computer program product comprising a non-transitory computer-readable medium containing an information processing program, the program causing a computer to function as:

a light source control unit that controls a light source device such that a specimen surface of a specimen is irradiated with illumination light from multiple illumination units at a plurality of illumination angles;

an image capturing control unit that controls a spectral camera device arranged above the specimen surface such that reflected light from the specimen surface is spectrally separated to acquire 2D spectral information through a single image capturing operation; and

a calculating unit that calculates deflection angle spectral information of the specimen surface used to measure a measurement value of a certain evaluation item of the specimen using a change in an optical geometrical condition of an illumination direction and an image capturing direction between pixels in an X axis direction and a Y axis direction of the spectral information.