Lecture 6 Histogram
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Computer Science E-7 Exposing Digital Photography Lecture 6: The Histogram October 19, 2009 [email protected] 1
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Lecture 6 Histogram
Transcript of Lecture 6 Histogram
Computer Science E-7Exposing Digital Photography
Lecture 6: The HistogramOctober 19, 2009
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Histograms General Histogram
Image from http://en.wikipedia.org/wiki/Histogram
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Histograms Digital Photography
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Black WhiteSome
Many
Histograms Total Underexposure
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Histograms Total Overexposure
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Histograms Well-exposed samples
Photo by Dan Armendariz, 2009309s, ISO 100
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Histograms Well-exposed samples
Photo by Dan Armendariz, 20071/1000s, ISO 400, f/5.6
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Histograms Well-exposed samples
Photo by Dan Armendariz, 2007
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Histograms
Under-exposure
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Photo by Dan Armendariz, 2005
8.0s, ISO 100, f/8
Histograms
Over-exposure
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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
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Histograms Over- & Under-exposure
Photo by Dan Armendariz, 20061/80s, ISO 400, f/10
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Bits and Bytes Refresher
Bit 0 or 1
Byte 8 bits
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Bits and Bytes As related to histograms
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Black White0 255
Bits and Bytes Bit Depth
JPEG
Red Green Blue
8-bit 8-bit 8-bit
0 255 0 255 0 255
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Histograms What about color?
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Red Green Blue
?
The Eye Luminance Detection
Image from http://en.wikipedia.org/wiki/Trichromacy
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The Eye Luminance Detection
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Red Green Blue
Luminance Calculation
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Luminance ≈ 0.3 R + 0.59 G + 0.11 B
Luminosity Histograms DIY!
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Luminosity Histograms DIY!
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Luminosity Histograms DIY!
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Histograms More than just Luminosity...
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Lum
R
B
G
Histograms Luminosity, Colors, & RGB
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Lum
Colors
RGB
Histograms Luminosity, Colors, & RGB
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Images from http://www.cambridgeincolour.com/tutorials/histograms2.htm
Histograms Luminosity, Colors, & RGB
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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
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Dynamic Range The Eye
Image from http://en.wikipedia.org/wiki/Fovea
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Dynamic Range Digital Cameras
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Pixel (“Bucket”)
Photons (Light)
Collected Light
Dynamic Range Simplified Calculation
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Dynamic Range =Biggest Signal (full “bucket”)Smallest detectable signal
Dynamic Range In Scenes
Photo by Dan Armendariz, 20061/80s, ISO 400, f/10
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Computer Science E-7Exposing Digital Photography
Lecture 6: The HistogramOctober 19, 2009
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