Optical grid enhancement for improved motor location

• US 8,976,368 B2
• Filed: 09/14/2012
• Issued: 03/10/2015
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Serres, Bernard, El Akel, Khalid, Stang, Jean-Pierre
• Primary Examiner(s): Geisel, Kara E
• Assistant Examiner(s): Underwood, Jarreas C
• Application Number:
  US13/616,367
• Publication Number:
  US 20140078515A1
• Time in Patent Office: 907 Days
• Field of Search: 3562371-2416, 3562421-2438, 356426-431, 356600-640
• US Class Current: 356/614
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01B 11/167 by projecting a pattern on the object
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/28 for measuring areas
• CPC Class Codes: G02B 7/09 adapted for automatic focusing or varying magnification
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03

Abstract

Methods for performing a scheme that results in a refined measurement pattern within an optical grid are provided. Physically adjusting spacing of elements within an optical grid to achieve enhanced resolution is historically unfeasible, as reduction of the spacing causes light sensors of the optical grid to pick up false signals when reading light beams. Technology introduced by the present invention generates a virtual reduced spacing of the elements within the optical grid by using two signals that are slightly different. These slightly different signals can accomplish, at least, quarter-grid spacing resolution within the optical grid. Additionally, the enhanced resolution derived from the virtual reduced spacing is employed to govern movement of a motor. The motor movement is in response to one or more changes of direction such that the motor is operating in its linear range. Advantageously, the virtual reduced spacing allows for substantial movement in a non-linear phase, while only limited movement in a linear phase is necessary to locate accurately a target within the optical grid.

Claims

1. One or more non-transitory computer-readable storage media having computer-useable instructions embodied thereon for performing a method of virtually reducing spacing of components within an optical grid by detecting wavelengths of light emitted from at least a single light source impinging upon the optical grid, the method comprising:

receiving input from a first beam of light by reading the first beam of light using a first sensor and a second sensor, wherein the first sensor is spatially offset from a the second sensor;

based on the input, deriving a pattern of transitions as a function of the spatial off set between the first sensor and the second sensor, wherein the pattern of transitions includes one or more transitions that correspond with one or more visual elements, respectively, of the optical grid; and

recording the pattern of transitions in association with clock cycles that are stored against the one or more transitions therein;

wherein a signal curve of the first-beam wavelength and a signal curve the second-beam wavelength are out-of-phase.

2. The computer-readable storage media of claim 1, wherein deriving the pattern of transitions comprises measuring when the signal curve of the first-beam wavelength produces a high signal.

3. The computer-readable storage media of claim 2, wherein deriving the pattern of transitions further comprises measuring when the signal curve of the second-beam wavelength produces a high signal.

4. The computer-readable storage media of claim 3, wherein deriving the pattern of transitions further comprises applying an algorithm to the signal-curve measurements to identify a transition when either the first-beam wavelength or the second-beam wavelength exclusively produces the high signal.

5. The computer-readable storage media of claim 1, wherein the components of the optical grid include a first light source for emitting the first beam of light.

6. The computer-readable storage media of claim 5, wherein the components of the optical grid include a second light source for emitting the second beam of light.

7. The computer-readable storage media of claim 6, wherein the pattern of transition is derived upon the first beam of light and the second beam of light emitted from the first and second light sources, respectively, being refracted from the visual elements of the optical grid and being received by the light sensor.

8. A computerized method for utilizing a motor to locate a target between visual elements of an optical grid, the method comprising:

accessing a pattern of transitions derived from measuring one or more beams refracted from the optical grid;

calibrating the motor by counting clock cycles of spacing that separate adjacent transitions within the pattern of transitions;

using the pattern of transitions to advance the motor in a forward direction at a non-linear rate;

upon reaching the target, stopping the motor and counting clock cycles between the target and a transition, within the pattern of transitions, immediately before the target;

operating the motor in a reverse direction until the target and the transition immediately before the target are passed; and

using the counted clock cycles to advance the motor from the transition immediately before the target in the forward direction at a linear rate to locate the target.

9. The computerized method of claim 8, wherein scanning comprises identifying the target is encountered when moving the motor in the forward direction.

10. The computerized method of claim 9, wherein scanning further comprises recording the clock cycles that elapsed between passing the transition immediately before the target and encountering the target.

11. The computerized method of claim 10, wherein locating comprises beginning forward movement of the motor from the transition immediately before the target while counting down the recorded clock cycles.

12. The computerized method of claim 11, wherein locating further comprises stopping movement of the motor upon completion of counting down the recorded clock cycles, wherein a position of the motor upon stopping corresponds with a location of the target on the barcode.

13. A computer system for performing a method of locating a target on a substrate, the computer system comprising a processor coupled to a computer-readable storage medium, the computer-readable storage medium having stored thereon a plurality of computer-software components executable by the processor, the computer software components comprising:

a resolution component that receives inputs from one or more light sensor provided within an optical grid, wherein the inputs indicate one or more beams of light refracting off the substrate and meeting the one or more light sensors;

a processing component that performs an exclusive-or operation using the inputs received by the resolution component and that generates a pattern of transitions from results of the exclusive-or operation;

a characterization component that calibrates a motor, wherein the motor calibration determines a non-linear operating region and a linear operating region of the motor, and wherein the motor is configured to move the substrate forward or rearward with respect to the optical grid; and

a communication component that interacts with the motor to locate the target using the pattern of transitions, wherein locating the target comprises;

(a) identifying a particular transition within the pattern of transitions that exists a number of clock cycles before the target;

(b) counting down the number of clock cycles while the motor is moving the substrate within the linear operating region from the particular transition toward the target; and

(c) instructing the motor to stop movement of the substrate upon the clock cycles being count down, wherein the one or more light sensors are substantially aligned with the target upon stopping the motor.

14. The computer system of claim 13, wherein at least one beam of light is emitted from a light source provided within the optical grid.

15. The computer system of claim 14, wherein the beams of light are emitted with similar wavelengths, while a timing of the beams of light is offset such that the wavelengths are out of phase.

16. The computer system of claim 15, wherein the beams of light include a first beam of light and a second beam of light that includes a second-beam wavelength that is out of phase from a first-beam wavelength of the first beam of light.

17. The computer system of claim 16, wherein the processing component is further configured to interpret the inputs received from the one or more light sensors, and wherein interpreting comprises:

recognizing two separate signals from the first beam of light;

using the recognized signals to identify when the first-beam and second-beam detectors produce respective high signals; and

performing the exclusive-or operation that determines a transition from the high signal exclusively produced by the first beam of light to the high signal exclusively produced by the second beam of light.

18. The computer system of claim 17, wherein the substrate represents an optical grid with visual elements that refract the first and second beams of light to the one or more light sensors, and wherein the results of the exclusive-or operation include providing a quarter-wavelength resolution between the visual elements.

19. The computer system of claim 18, wherein the motor represents a piezo motor that advances the object forward or retracts the object rearward under the direction of the communication component.