Large depth of field imaging technology & it’s phase shift control

XIA Chun-lei; ZHENG Gang; DAI Shu-guang

The role of cubic phase plate in large-depth-of-field diffraction limited system with CCD detector was discussed and the special phase shift phenomena caused by the cubic phase plate was studied.Mathematic functions indicating the relation between axial desfocus parameter ψ,cubic phase plate shape constant α and modulation transfer funetion(MTF) and image shift variable s were deduced.Spoke images for standard imaging system and that with large depth of field were shown when defocus variable w equals to 0,50,150 and 300 times wavelength respectively.Changing optical transfer function and reducing its sensitivity to axial defocus parameter,depth of field for imaging system was enlarged.Along with its enlargement,phase shift appeared simultaneously,which is related with both the extending ratio for depth of field and the constant for cubic phase plate.Thus phase shift could be very small and a satisfactory image might be achieved when the extending ratio was limited to a certain suitable range and a reasonable constant for cubic phase plate was chosen.

1. Optical & Electronical Information Engineering College, University of Shanghai for Science and Technology, Shanghai 200093, China

Received Date: 2007-01-29

Accepted Date: 2007-04-16

Available Online: 2008-04-25

Abstract: The role of cubic phase plate in large-depth-of-field diffraction limited system with CCD detector was discussed and the special phase shift phenomena caused by the cubic phase plate was studied.Mathematic functions indicating the relation between axial desfocus parameter ψ,cubic phase plate shape constant α and modulation transfer funetion(MTF) and image shift variable s were deduced.Spoke images for standard imaging system and that with large depth of field were shown when defocus variable w equals to 0,50,150 and 300 times wavelength respectively.Changing optical transfer function and reducing its sensitivity to axial defocus parameter,depth of field for imaging system was enlarged.Along with its enlargement,phase shift appeared simultaneously,which is related with both the extending ratio for depth of field and the constant for cubic phase plate.Thus phase shift could be very small and a satisfactory image might be achieved when the extending ratio was limited to a certain suitable range and a reasonable constant for cubic phase plate was chosen.

HTML

Reference (12)

[1]	WELFORD W T.Use of annular apertures to increase focal depth[J].Journal of the Optical society of America,1960,50(8):749-753.
[2]	LIU P Sh,LÜ B D.Boundary diffraction wave theory of plane wavesdiffracted at an annular aperture[J].Laser Technology,2006,36(1):110-112(in Chinese).
[3]	WALDKIRCH M V,LUKOWICZ P,TROESTER G.Multiple imaging technique for extending depth of focus in retinal displays[J].Optics Express,2004,12(25):6350-6365.
[4]	DOWSKI E R,Jr,CATHEY W T.Extended depth of field throughwavefront coding[J].Appl Opt,1995,34(11):1859-1866.
[5]	KUBALA K,DOWSKI E R,CATHEY W T.Reducing complexity in computational imaging systems[J].Optics Express,2003,11(18):2102-2108.
[6]	SOMAYAJI M,CHRISTENSEN M P.Enhancing form factor and light collection of multiplex imaging system by using a cubic phase mask[J].Appl Opt,2006,45(13):2911-2923.
[7]	GRACHT J V,EULISS J W.Information-optimized extended depth-of -field imaging system[J].Proc SPIE,2001,4388:103-112.
[8]	CATHEY W T,DOWSKI E R.New paradigm for imaging system[J].Appl Opt,2002,41(29):6080-6092.
[9]	SHERIF S S,DOWSKI E R,CATHEY W T.Effect of detector noise in incoherent hybrid imaging systems[J].Opt Lett,2005,30(10):566-568.
[10]	DOWSKI E R,JOHNSON G E.Wavefront coding:a modern method of achieving high performance and/or low cost imaging systems[J].Proc SPIE,1999,3779:137-145.
[11]	HELLMUTH T,BICH A,BRRET R,et al.Variable phase plates for focus invariant optics[J].Proc SPIE,2005,5962:15-25.
[12]	TIAN J Y,GONG M L,YAN P,et al.The design of bi-2aspherical single objective lens with numerical aperture of 0.85[J].Laser Technology,2005,29(2):116-118(in Chinese).

Large depth of field imaging technology & it’s phase shift control

Abstract

References

Proportional views

通讯作者: 陈斌, bchen63@163.com

Proportional views