EE 193 Imaging systems: Human color perception Steven Bell 20 - - PowerPoint PPT Presentation

▶

ee 193 imaging systems human color perception

EE 193 Imaging systems: Human color perception Steven Bell 20 - - PowerPoint PPT Presentation

Mar 07, 2023 199 likes •401 views

EE 193 Imaging systems: Human color perception Steven Bell 20 September 2018 Objectives Given a multispectral image of a scene and a spectral response curve, predict the appearance of the scene. Roughly sketch the spectral response curves

slide-1

SLIDE 1

EE 193

Steven Bell 20 September 2018

Imaging systems: Human color perception

slide-2

SLIDE 2

Objectives

Given a multispectral image of a scene and a spectral response curve, predict the appearance of the scene. Roughly sketch the spectral response curves for L, M and S cones. Explain what metamers are and why they occur. Predict the effect of various forms of color blindness.

slide-3

SLIDE 3

This is a ball.

slide-4

SLIDE 4

(wikipedia)

R O Y G B V

380 450 495 570 590 620 750

Wavelength (nm)

slide-5

SLIDE 5

Daylight (D65)

(wikipedia)

slide-6

SLIDE 6

Other spectra

http://www.chemistryland.com/CHM107Lab/ Exp7/Spectroscope/Spectroscope.html

slide-7

SLIDE 7

Reflectance

Surfaces reflect wavelengths differently

slide-8

SLIDE 8

Seeing color

The eye has 3 types of cones: "long", "medium", and "short"

400 450 500 550 600 650 700 Wavelength (nm) Normalized cone response (linear energy) S M L

(modified from Wikipedia)

slide-9

SLIDE 9

Cone response

400 450 500 550 600 650 700 Wavelength (nm) Normalized cone response (linear energy) S M L

=

L

slide-10

SLIDE 10

Medium cone response

400 450 500 550 600 650 700 Wavelength (nm) Normalized cone response (linear energy) S M L

=

M L

slide-11

SLIDE 11

Short cone response

400 450 500 550 600 650 700 Wavelength (nm) Normalized cone response (linear energy) S M L

=

S M L

slide-12

SLIDE 12

More cone responses

400 450 500 550 600 650 700 Wavelength (nm) Normalized cone response (linear energy) S M L

slide-13

SLIDE 13

This is a ball.

slide-14

SLIDE 14

Metamers

Any two objects with different spectra but identical cone responses are called metamers. (MetaCow under D65 illumination)

slide-15

SLIDE 15

Metamers

Any two objects with different spectra but identical cone responses are called metamers. (MetaCow under Illuminant A)

slide-16

SLIDE 16

Metamers and lighting

Given what you know about metamers and light, how should we design lighting to make things "look good"? What are "good spectra" for our light bulbs to have?

slide-17

SLIDE 17

Fluorescent spectra

Fluorescent bulbs work by exciting a mix of gases.

slide-18

SLIDE 18

LED spectra

LEDs emit more or less pure wavelengths. How do we get white?

slide-19

SLIDE 19

Color blindness

What would happen if you were missing your L cones?