Optical Engineering 4512, 127201 December 2006 Depth from mo(8)

One of the essential problems in computer vision is to recover the distance information of an object from captured images. Its application areas range from industrial inspection and reverse engineering to autonomous robot navigation

“character”image .Thecameramotionspeedis230mm/s.

Aperture0.8mm

Distance mm 500750100012501500

x10974564537

z1545805

z2549807

e1

e2

x

Aperture1.8mmz1547803

z2551805

e1

e2

Acknowledgment

ThesupportofthisworkinpartbytheNationalScienceCouncilofTaiwanundergrantNSC-93-2218-E-194-024isgratefullyacknowledged.

8.99.81097.47.6

74564436

9.410.27.15.47.5

7.35.88.7

106610716.67.1131113234.95.9160116276.78.5

1054105813441358

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scenedistanceperpendiculartotheimageplaneisnotaconstantfordifferentimageacquisitionpositions.Thus,themotionblurredimageiscapturedwhenthecamerareachesthedepthmeasurementposition i.e.,theplacerightinfrontoftheobject’scenter .

Tables6and7showtheexperimentalresultsusingthe“edge”image,withcameramotionspeedsof115and230mm/s,respectively.Theresultsofthe“character”im-agearetabulatedinTables8and9withtwodifferentcam-eramotionspeeds.Equations 20 and 27 areusedfordepthcomputationwiththeangle =15deg.

FromtheexperimentalresultsshowninTables2–9,mostoftherelativeerrorsarelessthan10%.Theresultssuggestthatthereisalinearrelationbetweenthetruedis-tanceandtherecovereddepth.Basedontheproposedcam-eramodel,theparametersgivenbythedepthrecoveryfor-mulasaretheerrorsources.Inadditiontothepossibleerrorcausedbytheincorrectnessofthecameraparameters,theaccuracyofthemotionspeed controlledbythesteppingmotor andblurextentestimationwillalsoaffectthecor-rectnessofthedepthmeasurement.

5ConclusionandFutureWork

Findingthedistanceofanobjectinasceneisanessentialprobleminmanyapplications.Severalapproachesbasedondifferentvisualcuesobservedfromimageshavebeenpro-posedinthepastfewdecades.Inthiswork,wepresentanovelapproachfordepthrecoveryfromasinglemotionanddefocusblurredimage.Differentfrompreviousdepthfromdefocusapproaches,whichusedatleasttwoblurredimages,ourmethodrequiresonlyasingledefocusedimagetorecoverthedepthofascene.Furthermore,thecalibrationstageforourdepthrecoveryalgorithmismuchsimplercomparedtothegeneraldepthfromfocusapproaches.Itisshownthat,inmostcases,defocusblurcanbeignoredinthepresenceofmotionblur.Infuturework,robustblurparameterestimationformorecomplexsceneswillbede-veloped.Depthmeasurementofoutdoorsceneswillbecar-riedoutbycapturingtheblurredimagesfrommovingob-