EE 638: Principles of Digital Color Imaging Systems Lecture 30.2

Model assumptions for Layer1 Kruse-Gustavon model Microscopic model Linear system Model assumptions for Layer1 Within colorant, assume ideal point-to-point interaction for scatter Use multiplicative model to represent absorptance in passing through colorant colorant substrate Layer 1 (1) (2) (3) (4)

Layer 2: this is where scattering takes place Aside Thin optical element Assume Layer 2: this is where scattering takes place Aside covered area transmittance of colorant uncovered area transmittance of area not covered with colorant

Spatial frequency model: Point spread of media: (2) (3) Recall temporal frequency Spatial frequency model: Point spread of media: not a spatial model but rather macroscopic stimulus reflection incident Wavelength dependent scattering Spectral reflectance of paper

Should adopt a spectral model for colorant-light interaction, as well: Layer 3 – Stage 3 to stage 4 Note that this is 2-D spatial convolution only! Initially incident on print at top of colorant layer Light that reaches surface of media Light that emerges from media after scatter within media Light that emerges from print after passing back through colorant layer Question: How would we compute the CIE XYZ coordinates of the reflected light?