lecture 6 histogram
DESCRIPTION
Lecture 6 HistogramTRANSCRIPT
Computer Science E-7Exposing Digital Photography
Lecture 6: The HistogramOctober 19, 2009
1
Histograms General Histogram
Image from http://en.wikipedia.org/wiki/Histogram
2
Histograms Digital Photography
3
Black WhiteSome
Many
Histograms Total Underexposure
4
Histograms Total Overexposure
5
Histograms Well-exposed samples
Photo by Dan Armendariz, 2009309s, ISO 100
6
Histograms Well-exposed samples
Photo by Dan Armendariz, 20071/1000s, ISO 400, f/5.6
7
Histograms Well-exposed samples
Photo by Dan Armendariz, 2007
8
Histograms
Under-exposure
9
Photo by Dan Armendariz, 2005
8.0s, ISO 100, f/8
Histograms
Over-exposure
10
Photo by Dan Armendariz, 2005
15.0s, ISO 100, f/16
Histograms Exposure Compensation
Photos by Dan Armendariz, 2005Left: 1/80s, ISO 400, f/2.8, 0ev. Right: 1/80s, ISO 800, f/2.5, +1.3ev
11
Histograms Over- & Under-exposure
Photo by Dan Armendariz, 20061/80s, ISO 400, f/10
12
Bits and Bytes Refresher
Bit 0 or 1
Byte 8 bits
13
Bits and Bytes As related to histograms
14
Black White0 255
Bits and Bytes Bit Depth
JPEG
Red Green Blue
8-bit 8-bit 8-bit
0 255 0 255 0 255
15
Histograms What about color?
16
Red Green Blue
?
The Eye Luminance Detection
Image from http://en.wikipedia.org/wiki/Trichromacy
17
The Eye Luminance Detection
18
Red Green Blue
Luminance Calculation
19
Luminance ≈ 0.3 R + 0.59 G + 0.11 B
Luminosity Histograms DIY!
20
Luminosity Histograms DIY!
21
Luminosity Histograms DIY!
22
Histograms More than just Luminosity...
23
Lum
R
B
G
Histograms Luminosity, Colors, & RGB
24
Lum
Colors
RGB
Histograms Luminosity, Colors, & RGB
25
Images from http://www.cambridgeincolour.com/tutorials/histograms2.htm
Histograms Luminosity, Colors, & RGB
26
Images from http://www.cambridgeincolour.com/tutorials/histograms2.htm
Histograms What is Black and White?
Photo by Dan Armendariz, 20061/80s, ISO 400, f/10
27
Dynamic Range The Eye
Image from http://en.wikipedia.org/wiki/Fovea
28
Dynamic Range Digital Cameras
29
Pixel (“Bucket”)
Photons (Light)
Collected Light
Dynamic Range Simplified Calculation
30
Dynamic Range =Biggest Signal (full “bucket”)Smallest detectable signal
Dynamic Range In Scenes
Photo by Dan Armendariz, 20061/80s, ISO 400, f/10
31
Computer Science E-7Exposing Digital Photography
Lecture 6: The HistogramOctober 19, 2009
32