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A Robust Similarity Measure For Automatic Inspection. Omer Barkol joint work with Hadas Kogan, Doron Shaked and Mani Fischer HP Labs, Israel September 2010. THE CHALLENGE. Print-inspection of print-speed variable-data input Compare two images from different acquisition devices
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A Robust Similarity Measure For Automatic Inspection Omer Barkol joint work with Hadas Kogan, Doron Shaked and Mani Fischer HP Labs, Israel September 2010
THE CHALLENGE Print-inspection of print-speed variable-data input Compare two images from different acquisition devices Dissimilarities to ignore: color, spatial deformation Avoid false alarms Scanner Digital Reference Scanned Image Reference Image
Inspection DEMOED @ IPEX 2010 Capability demonstrated on Indigo-7500 press
SIMILARITY MAP reference similarity map scan
SIMILARITY MAP Sub-pixel misregistration Locally varying reference similaritymap scan
GOAL: Improved similarity measure – insensitive to (locally varying) sub-pixel misregistration Digitalreference Scannedimage
SP SIMILARITY MEASURE “Definition”: SM(x,y) respects convex combinations if for any 0≤a≤1, SM(x,y) ≤ SM(x,ax+(1-a)y) ax+(1-a)y y x 9 2 ) + ( ) = ( 11 11 • 100 90 0 100 200 • 90 100 110
SP SIMILARITY MEASURE Let SM be a similarity measure that respects convex combinations Let x’ is the patch x shifted by 1 pixel and GSM(x)=SM(x,x’) GSM(x)=minx’ in Nx(SM(x,x’)) x’ x Recall: GSM(x) = SM(x,x’) ≤ SM(x,ax+(1-a)x’)= SM(x,y) y Then define SPSM(x,y) = SM(x,y) / GSM(x) min(1,SM(x,y)/GSM(x))
structure luminance contrast Shift by 0.5 pixel + 3 defects Original image SSIM result EXISTING SIMILARITY MEASURE • SSIM (Structure SIMilarity measure) – • State-of-the-art image measure that reflects human perception Sensitive to sub-pixel misregistration Use SPSSIM PROBLEM: SSIM does not respect convex combinations * Z. Wang, A.C. Bovik, H.R. Sheikh, and E.P. Simoncelli. Image quality assessment: From error visibility to structural similarity. IEEE Transactions on Image Processing, 13:600–612, 2004.
structure luminance contrast EXISTING SIMILARITY MEASURE ax+(1-a)y y x might be negative
inner product REVISED SIMILARITY MEASURE respects convex combinations
SPSSIM SIMILARITY MEASURE SPSM SPSM We then define
SPSSIM - RESULTS Shift by 0.5 pixel + 3 defects Originalimage SSIMresult SPSSIMresult
SPSSIM - RESULTS Reference Scan SSIM SPSSIM
SPSSIM - RESULTS False alarm 2-D sub-pixel shift SPSSIM False alarms rate original SSIM ~ SSIM Miss detection random Miss detections rate
RECAP ON SPSSIM • Introducing two contributions: • Revise SSIM to respect convex combinations • Define a new paradigm SPSM creating SPSSIM
INSPECTION HARDWARE Overview Duplex and Variable resolution Scanners GPU enhanced computing
INSPECTION SOFTWARE OVERVIEW Press GUI print configuration results CMYK reference iDo Vcorn XML XML iVision Orchestrator images ILS Scanners RGB scans Inspection config images File system inspect
INSPECTION SYSTEM OVERVIEW AviMalki Nechama, Yair, Silvia Ofer,Anna Press Leonid, Alex, Andrey GUI print configuration iDo Vcorn iVision Michael, Nataly, Lena Orchestrator ILS Scanners Rodolfo Inspection HPLI File system inspect
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze Hadas Mani Hadas Marie Sagi Sagi Marie Mani CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press Hadas, Doron,Mani iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze Alex Carl Michal inspection GPU Image Saving Distributed multi-threaded with GPU part
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
Reference INPUT IMAGES CMYK 203.2x81.28 dpi Scans RGB 200x80 dpi The Job 812.8 dpi
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
CMYK to RGB 7x7x7x7 Conversion table
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
Registration initial scale final color and size adjustments initial scale scale and offset crude affine transform adjustments
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
Bands & streaks bands streaks dust streaks
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
ANALYSIS Ignore faint / thin / small blobs find strong blobs and combine close ones report on original locations original reference original scan SPSSIM map
CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze INSPECTION: HIGH LEVEL COMPONENTS Press iVision CMYK 2 RGB Registration Color Monitoring Bands, streaks & dust streaks Compare: SPSSIM Analyze inspection GPU Image Saving
FUTURE • Enhance robustness to different spatial deformation • Collect trends in a series of images • Allow inspection to give automatic feedback to the machine – self repair