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Color Image Processing

What type of projects or assignments help looking for?​

  • Assignment or Project Help

  • Online Training and Mentorship

  • New Idea or project

  • Existing project that need more resources

Why do we use color image

  • In automated image analysis, color is a powerful descriptorÆ simplify object identification and extraction from a scene

  • For human visionÆ human eye can discern thousands of color shades and intensities (only two dozen shades of gray)

Color Image Processing Techniques

  • Full color – image is acquired with a full-color sensor like TV camera or color scanner

  • Pseudo color – Assign a color to a range of monochrome intensities

  • The availability of inexpensive and powerful hardware has resulted in the proliferation of applications based on full color processing

Color fundamentals

  • Color spectrum/prism

  • Color

  • Characterization of light

  • Chromatic light

  • Light source characterized by three quantities

    • Radiance Total amount of energy emitted by light source

      • Physical power of light energy, measured in watts

      • Directional quantity

      • Measures the quantity of radiation that passes through or emitted from a surface and falls within a given solid angle in a specified direction

      • Expressed in a spectral power distribution, often in 31 components, each representing a 10 nm band

      • Historically, also called intensity

    • Brightness Achromatic notion of intensity to describe color sensation

      • Attribute of a visual sensation according to which an area appears to emit more or less light

      • Subjective attribute of an object being observed

      • Cannot be measured quantitatively

    • Luminance Measure of amount of energy as perceived by an observer, measured in lumens or candelas per square meter

      • Light may contain a lot of energy in IR bands but that is not perceptible to the observer

      • More tractable version of brightness, defined by CIE

      • Radiant power weighted by a spectral sensitivity function that is characteristic of vision

      • Luminous efficiency peaks at 555nm

      • CIE luminance, denoted by Y , is the integral of spectral power distribution, using spectral sensitivity curve as a weighting function

      • Magnitude of luminance is proportional to physical power, but spectral composition is related to brightness sensitivity of human vision

      • Units of measurement for image processing

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