Spectrophotometer Jan 28, 2002 Deryck Hong Suryadi Gunawan

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Spectrophotometer Jan 28, 2002 Deryck
HongSuryadi Gunawan
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Presentation Outline

• Project Objective
• Project Specification
• Design
• Test Plane
• Power Consumption
• System cost

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Project Objective

• Building a measurement tool that is used to
  measure color composition
• Measures light reflected from an object at each
  wavelength.
• Creating a color spectrum and measuring intensity
  of each color.
• Using the intensities to create the color of the
  object and displaying the color on a screen with
  corresponding RGB values.
• The object has to be a piece of single colored
  paper

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Project Specification

• CCD sensor
• 2048 pixels
• Blue 150 650
• Green 800 1300
• Red 1450 - 1950
• Intensity from 0 - 255
• Lens
• Focal length of 80 mm
• Distance between object and lens is 5 cm
• Distance between lens and the CCD sensor is 13 cm
• Accuracy
• Error within (10)

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Project Specification

• Using C programming with GRX graphic library to
  create GUI
• Communication between PC and the CCD sensor
  through parallel port

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Color Spectrum

• This project uses the wavelengths from 435 nm to
  740 nm.

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Design
Parallel Port
Source
Lens
Diffraction Grating
CCD Sensor
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Design Cont

• The distances between parts have to be
  calculated
• Between Diffraction Grating and the lens
• Between Diffraction Grating and the CCD sensor
• Distance between the lens and the Diffraction
  Grating can be calculated using lens equation
• 1/Object distance 1/Image distance 1/focal
  length

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Design Cont.

• After finding the angles, the distance (D) can be
  calculated using the following equations
• and are the displacements from the
  central maxima to the maxima of blue and red
  lights. The difference of those two
  displacements has to be the height of the CCD
  sensor.
• The height of the CCD sensor 2048 14um
  2.867cm
• Then D is found to be 2.867cm/0.6172 5 cm

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Division of Work

• Hardware ( Deryck Suryadi)
• Mounting of parts
• Casing
• Placing of light
• Software
• Parallel port communication ( Deryck Suryadi)
• GUI ( Deryck )
• Algorithm ( Suryadi)

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Work Completed

• CCD, Lens and grating have been mounted.
• Light has been placed.
• Casing is created.
• Light absorption is designed.
• GUI is done
• Parallel port communication between CCD sensor
  and PC is done
• Still have some small problems
• System calibration is done
• Pixels that correspond to Red, Green, and Blue
  are found

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Work to be done

• Algorithm is implemented but still needs to be
  fully tested.
• Overall system testing
• Color Compensation for monitor viewing

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Test Plan

• Use Color samples that has known RGB values to
  test the system
• A set of color samples have been measured using
  the device in the color laboratory in printing
  department
• The device measures the LAB values of the color
  samples
• Then the LAB values are converted to RGB values
• This set of color samples will be used to test
  the system.

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Power consumption

• CCD board 5 watts
• Light source.50 watts
• Total power consumed.55 watts

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System cost

• CCD and lens1040
• Grating1
• Casing. free
• Light source30
• Misc (tape, black paper, etc)15
• total 1086

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Question