INTERMEDIATE LEVELS A few intermediate levels can provide
- Slides: 16
INTERMEDIATE LEVELS ”A few intermediate levels can provide a substantial improvement”
Human vision -Contrast sensitivity function (CSF) ~30 cycles/deg for 20/20 vision -Sensitive for disturbances with 0. 5 -10 mm wavelength for normal reading distance -Perceptible luminance modulation ~200 tone levels For normal reading distance
MULTILEVEL HALFTONE SCREEN Uniform quantizer
MULTILEVEL HALFTONE SCREEN Non-uniform quantizer
MULTILEVEL SCREEN OPTIMIZATION Theoretical upper limit of possible tone level combinations for a cell with Np number of pixels gmax tone levels per pixel
MULTILEVEL SCREEN OPTIMIZATION In practice, the distinguishable levels are much lower because of redundancy in tone level arrangements the difference between some levels is too small to be resolved visually
REDUNDANCY 2 x 2 Trilevel Halftone cells – 15 Reflectances
REDUNDANCY 2 x 2 Trilevel Halftone cells – 9 Unique Reflectances
REDUNDANCY Ravg = 0. 25
OPTIMIZATION TRC ~ optical density out vs. optical density in Performance evaluation RMS-fit to 45° line
OPTIMIZATION Density is not linear to human visual perception Solution, a more linear measure of brightness response Munsell value L for Ravg> 0. 05
OPTIMIZATION
OPTIMIZATION
MULTILEVEL STOCHASTIC SCREEN – USE GENERIC APPROACH TO CREATE BNM DITHER MATRIX ERROR DIFFUSION – REPLACE THRESHOLD WITH QUANTIZER AND DIFFUSE THE QUANTIZATION ERROR COLOR HALFTONING - COLOR SCREEN SUPERIMPOSITION CAN BE USED DIRECTLY. METHOD FOR ERROR DIFFUSION (OSTROMOUKHOV…)
HIGH-ADRESSABILITY
INKJET 1. MULTIPLE DROPLETS 2. MULTIPLE NOZZLES – DIFFERENT ORIFICES 3. MULTIPLE INKJET HEADS – DIFFERENT INKS 4. USE SATELLITE DROPLETS COMBINATIONS OF 1 -4
- She's lucky she has few problems
- Few ja a few ero
- Fill in a few a little
- Complete the sentences with few a few little or a little
- Cognitive levels of assessment intermediate phase
- Cognitive levels of assessment: intermediate phase
- Intermediate artifact can be assessed by
- Costa's house questions
- "high levels of urea in the blood can result in"
- Rapidly progressive glomerulonephritis
- Why are there few examples of totem poles from before 1900?
- Most sayılabilen mi
- Few food or little food
- A lot of vs much many
- Which of the following few common services provided by os
- Mr jones had a few days holiday
- Metar reading practice