# US 8,570,523 B2 · Method for discriminating between objects

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- Number: US 8,570,523 B2
- Document ID: US8570523B2
- Status: Granted
- Kind: B2
- Application number: 12/874,256
- Filed: 2010-09-02
- Published: 2012-03-08
- Granted: 2013-10-29
- Earliest claimed: 2010-09-02
- Assignees: Eastman Kodak Company
- Applicants: Vitaly Burkatovsky
- Inventors: Vitaly Burkatovsky
- Web page: https://patentgrep.com/patent/US8570523B2

## CPC

- B65H 7/14: by photoelectric feelers or detectors
- G01N 21/55: Specular reflectivity
- B65H 2515/60: Optical characteristics, e.g. colour, light
- B65H 2553/414: involving receptor receiving light reflected by a reflecting surface and emitted by a separate emitter
- B65H 2557/61: for calibrating
- B65H 2557/64: for detecting type or properties of handled material
- B65H 2701/18264: Pile of alternate articles of different properties, e.g. pile of working sheets with intermediate sheet between each working sheet
- B65H 2701/1928: Printing plate
- G01N 21/57: Measuring gloss
- G01N 33/346: {Paper sheets}
- G01N 2021/556: {Measuring separately scattering and specular}
- G01N 2021/8427: {Coatings}
- B65H: HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method for discrimination between a first (308) and a second surface (304) type based on reflectivity has a light source (416) that illuminates on a media surface. A photosensor (420) receives and measures the reflection value from the surface. A first gain element adjusts a voltage from the photosensor and a second gain element adjusts a current measurement supplied to the light source. A subtractor (530) for subtracting the first adjusted voltage (534) and the adjusted measurement (538) are subtracted to provide an output value close to zero with respect to the second surface and near a maximum with respect to the first surface. The adjusted reflection value and a threshold reference value (428) are compared (124) and indicates whether the first surface or the second surface is present.

## Claims

### Claim 1

A method for discriminating between a first surface type and a second surface type wherein said first surface type's reflectivity is greater than said second surface type's reflectivity comprising:
illuminating said first or said second surface type with a light source;
measuring a reflectivity of said first surface type or said second surface type;
adjusting a voltage gain or current gain based on said measured reflectivity to provide a first adjusted voltage or current;
adjusting a measurement of a current or a voltage supplied to said light source;
subtracting the first adjusted voltage or current from the adjusted measurement to provide a subtractor output value;
providing a threshold reference value; and
comparing said subtractor output value with said threshold reference value to determine whether said first surface type or said second surface type is present.

### Claim 2 (depends on 1)

The method according to claim 1 wherein said light source is a LED.

### Claim 3 (depends on 1)

The method according to claim 1 wherein said second surface type is an emulsion covered surface.

### Claim 4 (depends on 1)

The method according to claim 1 wherein said first surface type is a slip sheet paper.