Analysis of CCD moiré pattern for micro-range measurements using the wavelet transform

Chang, Rong Seng; Sheu, Jin Yi; Lin, Ching Huang; Liu, He Chiang

doi:10.1016/s0030-3992(02)00122-6

Cited by 29 publications

(27 citation statements)

References 7 publications

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“…The thickness of the overcoating layer was 1.3 μm, so the RM molecules were aligned well by the geometric alignment effect of the nanogroove structure, without any additional alignment method. A fringe pattern caused by the moiré effect can be formed by superposition of periodic structures [19,20]. In our case, because of the nanogroove structure the fringe pattern can be observed, as shown in Fig.…”

Section: Fabrication Of the Rm Lens Arraymentioning

confidence: 51%

“…In addition, we realize an RM lens that has a high fill factor because the edge region of the RM lens can be aligned well by top-down alignment. In this case, because of diffraction and moiré fringes caused by the remaining nanogroove structure on top of the RM layer, the imaging quality can be diminished [19,20]. However, in our approach, by overcoating the same RM on the surface of the thick planoconvex RM layer, the polarization-dependent RM lens array can be planarized, providing an almost ideal lens profile.…”

Section: Introductionmentioning

confidence: 96%

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Polarization-Dependent Microlens Array Using Reactive Mesogen Aligned by Top-Down Nanogrooves for Switchable Three-Dimensional Applications

Son

Kim

Park

2015

Journal of the Optical Society of Korea

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We propose a reactive mesogen (RM) lens array to obtain good focusing behavior along with a short focal plane, where the focusing behavior is switchable according to the polarization state of incident light. Polarization-dependent focusing behavior is obtained using a planoconvex RM microlens array on a planoconcave isotropic lens template. Even though the sagitta of our RM lens is high, to obtain the short focal length, the RM layer can be aligned well by introducing a top-down alignment effect, using a nanogrooved template. The optical noise due to the moiré effect generated by the nanogrooves on the surface of the planoconvex RM layer can be removed simply by overcoating a thin RM layer, which is self-aligned by the geometric surface effect, without an additional alignment process. We demonstrate a hexagonal-packed RM lens array that has a very high fill factor and symmetric phase profile, for an ideal lens.

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Section: Fabrication Of the Rm Lens Arraymentioning

confidence: 51%

Section: Introductionmentioning

confidence: 96%

Polarization-Dependent Microlens Array Using Reactive Mesogen Aligned by Top-Down Nanogrooves for Switchable Three-Dimensional Applications

Son

Kim

Park

2015

Journal of the Optical Society of Korea

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“…2a shows the resulting 1-D image intensity profile. Notice that the extracted period p m of the Moiré fringe pattern can be easily obtained as there are no specimen line grating artifacts, as observed with the 300 lpi line gratings used in (Chang, 2003 …”

Section: Near Similar Pitch Gratingsmentioning

confidence: 98%

“…The interaction between the two 'gratings' results in the formation of Moiré patterns, which can be simply captured by the CCD camera itself. This imaging device-based approach of using Moiré fringes for surface displacement measurement was suggested by (Chang, 2003), where they demonstrated how wavelet transform (WT) could be used to extract the pitch of the Moiré fringes for micro-range measurement. A micro-pitch grating of 300 lines per inch (lpi) was employed as the specimen grating so that the pitch dimensions of the grating is close to that of the CCD cell spacing.…”

Section: Introductionmentioning

confidence: 99%

MOIRÉ PATTERNS FROM A CCD CAMERA - Are They Annoying Artifacts or Can They be Useful?

Tu¹,

Goh

2009

Proceedings of the Fourth International Conference on Computer Vision Theory and Applications

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Abstract:When repetitive high frequency patterns appear in the view of a charge-coupled device (CCD) camera, annoying low frequency Moiré patterns are often observed. This paper demonstrates that such Moiré pattern can useful in measuring surface deformation and displacement. What is required, in our case, is that the surface in question is textured with appropriately aligned black and white line gratings and this surface is imaged using a grey scaled CCD camera. The characteristics of the observed Moiré patterns are described along with a spatial domain model-fitting algorithm that is able to extract a dense camera-to-surface displacement measures. The experimental results discuss the reconstruction of planar incline and curved surfaces using only a coarse 33 lines per inch line grating patterns printed from a 600 dpi printer.

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“…5,6 The Moire method has a particularly unique advantage in that it can significantly improve the precision with no further demands on the sensitivity of the optical sensor. For this reason, the Moire method is widely used for optical displacement measurements in optical encoders 2,7,8 and curved surface metrology. [9][10][11][12] We attempt here to implement Moire technologies into ORMS in order to improve the measurement precision.…”

Section: Introductionmentioning

confidence: 99%

Optical displacement metrology using alternating direction Moire

et al. 2014

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Abstract. We develop a new double exposure Moire method for an optical registration metrology system in photolithography. Our method enables us to achieve at least a factor of 10 improvements in precise displacement metrology using a conventional optical sensor. We utilize a new registration mark printed to the photoresist on a bare silicon wafer using a double exposure of the gratings. The mark consists of two types of Moire with opposite phases. The two types of Moire are oriented in alternate directions. Displacement is measured from the distance between the positions of the two types of Moire in analogy with the conventional registration method. This concept is called alternating direction Moire. Performance is experimentally confirmed using an i-line wafer exposure apparatus. Precision is improved by up to 32 times as compared with the conventional method and can be applied to other Moire metrologies.

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Analysis of CCD moiré pattern for micro-range measurements using the wavelet transform

Cited by 29 publications

References 7 publications

Polarization-Dependent Microlens Array Using Reactive Mesogen Aligned by Top-Down Nanogrooves for Switchable Three-Dimensional Applications

Polarization-Dependent Microlens Array Using Reactive Mesogen Aligned by Top-Down Nanogrooves for Switchable Three-Dimensional Applications

MOIRÉ PATTERNS FROM A CCD CAMERA - Are They Annoying Artifacts or Can They be Useful?

Optical displacement metrology using alternating direction Moire

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