an evaluation of the current state of digital photography l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
An Evaluation of the Current State of Digital Photography PowerPoint Presentation
Download Presentation
An Evaluation of the Current State of Digital Photography

Loading in 2 Seconds...

play fullscreen
1 / 29

An Evaluation of the Current State of Digital Photography - PowerPoint PPT Presentation


  • 279 Views
  • Uploaded on

An Evaluation of the Current State of Digital Photography Charles Dickinson Advisor: Jeff Pelz Main Objective Gain a better understanding of the state of digital photography Overview Introduction Experimental Results Conclusions Review Introduction

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'An Evaluation of the Current State of Digital Photography' - jaden


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
main objective
Main Objective
  • Gain a better understanding of the state of digital photography
overview
Overview
  • Introduction
  • Experimental
  • Results
  • Conclusions
  • Review
introduction
Introduction
  • Goal: Evaluate digital photography from digital camera input to printer output
  • Metrics: MTF and subjective evaluation
questions to be answered
Questions to be Answered
  • Obtain a model for digital photography
  • What is gained by upgrading a camera / printer in a digital photographic system?
  • What are the effects of interline vs. frame transfer?
experimental
Experimental
  • Kodak DC120, DC260, DCS315, DCS460
  • Epson Stylus 800, Kodak 8670
  • Photoshop, IDL, Image Analyzer, Imlab
digital camera characterization
Digital Camera Characterization
  • Adopted slanted knife edge method
  • Software: PIMA Image Analyzer plug-in, ISO 12233
image analyzer
Image Analyzer
  • Calculates MTF given a slanted knife edge
  • Easy to use, robust edge angle, predicts MTF up to 4 times Nyquist frequency1
  • 1.)Benchmarking of the ISO 12233 Slanted-edge Spatial Frequency Response Plug-in, Don William, IS&T’s 1998 PICS Conference, pp 133-136
procedure
Procedure
  • Image target in upright position
  • Convert image to Lab space and remove a and b channels in Photoshop
  • IDL program takes rectangle within reflectance targets and averages values (Digital Count, dc)
procedure11
Procedure
  • Input dc values into Excel, plot vs. known reflectances
  • Fit trendline and calculate reflectances for 256 dc’s
  • In Photoshop, select ROI, use Image analyzer ‘filter’
  • Image analyzer calls for ‘OECF’
printer characterization
Printer Characterization
  • IDL creates sine patterns, print in Photoshop
  • Examine under microdensitometer with Imlab
  • Determine MTF with histogram of sine pattern
sine histograms
Sine Histograms

ideal

real

# pixels

# pixels

min

max

max

min

Reflectance

Reflectance

Modulation = (Rmax - Rmin) / (Rmax + Rmin)

subjective evaluation
Subjective Evaluation
  • Four questions: sharpness, color preference, color reproduction, overall quality
  • 1-10 rating
  • Image with DC120 and DCS460 printed on dye-sub and inkjet, traditional photograph
  • 5 x 7 inch prints
camera discussion
Camera Discussion
  • DCS460 performs best, DC120 worst
  • DC260 has edge enhancement
  • DCS315 performed worse than DC260
subjective results discussion
Subjective Results Discussion
  • DCS460, inkjet combination did the best for sharpness, color, but 460, dye-sub system did better overall
  • Photograph didn’t perform best in any category
  • For DC120, inkjet and dye-sub perform about the same
system results discussion
System Results Discussion
  • DC260/inkjet system performed the best
  • For DC120, DCS315: printer makes small change in MTF
  • For DC260, DCS460: printer makes large change in MTF
conclusions
Conclusions
  • Interline vs. frame transfer comparison can’t be done with DC260, DCS315
  • For low end camera, printer upgrade is insignificant to MTF
  • High end camera MTFs benefit from printer upgrade
  • Although inkjet has better MTF, dye-sub is more pleasing to eye
review
Review
  • Gain model for digital photographic systems
  • Accomplished, but:
    • MTF doesn’t completely describe system
    • Subjective evaluations for DC120, DCS460 only
special thanks
Special Thanks
  • Dr. Jeff Pelz
  • Dr. John Arney