Abstract

Although barcodes can be used to manage data conveniently, they cannot be applied to small areas. Therefore, pointcodes are used to overcome the issue in this article. A pointcode uses a pointcode pattern to encode data and uses a pointcode image to decode data. A pointcode pattern is composed of many grating dots with different specified grating pitches and grating orientations. Moreover, there are two grating-dot sizes generated. When a laser beam illuminates a pointcode pattern with correct illuminating conditions, a pointcode image corresponding to the hidden data is diffractively reconstructed. A pointcode image is composed of many bright points with different positions. There are two possible bright-point sizes generated. A bright point or two bright points at specified positions are used to denote a number. Small pointcode patterns are enough to diffractively form pointcode images.

© 2009 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]
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2008

2007

S. L. Yeh, “Identifying a dot-matrix hologram by the position-error curves of its grating dots,” Opt. Eng. 46, 025801 (2007).
[CrossRef]

2006

S. L. Yeh, “Dot-matrix hologram with an encrypted figure,” Opt. Eng. 45, 095801 (2006).
[CrossRef]

2003

S. L. Yeh and Y. K. Shen, “Optical matrix structure for optical interconnection between two groups of points,” Opt. Eng. 42, 2068-2074 (2003).
[CrossRef]

E. Marom, S. Kresic-Juric, and L. Bergstein, “Speckle noise in bar-code scanning systems--power spectral density and SNR,” Appl. Opt. 42, 161-174 (2003).
[CrossRef] [PubMed]

2002

Z. Zhong, J. Ding, Z. Jin, P. Liang, and G. Wenqi, “Self-focusing hidden bar code,” Appl. Opt. 41, 308-311 (2002).
[CrossRef] [PubMed]

S. L. Yeh and S. T. Lin, “Dot-matrix hologram with hidden image,” Opt. Eng. 41, 314-318 (2002).
[CrossRef]

1993

1992

Allebach, J. P.

Bergstein, L.

Bever, S. J.

Ding, J.

Goodman, J. W.

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, 1968).

Jin, Z.

Katz, J.

Kresic-Juric, S.

Liang, P.

Lin, S. T.

Marom, E.

Rhode, A.

A. Rhode and F. Ross, Holography Marketplace, 8th ed. (Ross Books, 1999).

Ross, F.

A. Rhode and F. Ross, Holography Marketplace, 8th ed. (Ross Books, 1999).

Shen, Y. K.

S. L. Yeh and Y. K. Shen, “Optical matrix structure for optical interconnection between two groups of points,” Opt. Eng. 42, 2068-2074 (2003).
[CrossRef]

Swartz, J.

Tsi, D.

Tu, Y. C.

Wenqi, G.

Yeh, S. L.

S. L. Yeh, S. T. Lin, and Y. C. Tu, “Diffractive barcode using grating-dot lines,” Opt. Lett. 33, 1942-1944 (2008).
[CrossRef] [PubMed]

S. L. Yeh, S. T. Lin, and Y. C. Tu, “Diffractive barcode using grating-dot lines,” Opt. Lett. 33, 1942-1944 (2008).
[CrossRef] [PubMed]

S. L. Yeh, “Identifying a dot-matrix hologram by the position-error curves of its grating dots,” Opt. Eng. 46, 025801 (2007).
[CrossRef]

S. L. Yeh, “Dot-matrix hologram with an encrypted figure,” Opt. Eng. 45, 095801 (2006).
[CrossRef]

S. L. Yeh and Y. K. Shen, “Optical matrix structure for optical interconnection between two groups of points,” Opt. Eng. 42, 2068-2074 (2003).
[CrossRef]

S. L. Yeh and S. T. Lin, “Dot-matrix hologram with hidden image,” Opt. Eng. 41, 314-318 (2002).
[CrossRef]

Zhong, Z.

Appl. Opt.

Opt. Eng.

S. L. Yeh and S. T. Lin, “Dot-matrix hologram with hidden image,” Opt. Eng. 41, 314-318 (2002).
[CrossRef]

S. L. Yeh and Y. K. Shen, “Optical matrix structure for optical interconnection between two groups of points,” Opt. Eng. 42, 2068-2074 (2003).
[CrossRef]

S. L. Yeh, “Dot-matrix hologram with an encrypted figure,” Opt. Eng. 45, 095801 (2006).
[CrossRef]

S. L. Yeh, “Identifying a dot-matrix hologram by the position-error curves of its grating dots,” Opt. Eng. 46, 025801 (2007).
[CrossRef]

Opt. Lett.

Other

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, 1968).

A. Rhode and F. Ross, Holography Marketplace, 8th ed. (Ross Books, 1999).

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Figures (12)

Fig. 1
Fig. 1

Grating dot used to reflectively diffract an incident beam to form an nth-order diffraction beam.

Fig. 2
Fig. 2

Number and assistant dots for the one-point two-size five-position method.

Fig. 3
Fig. 3

Number and assistant dots for the two-point two-size three-position method.

Fig. 4
Fig. 4

Grating-dot unit composed of 4 × 4 different diffraction units.

Fig. 5
Fig. 5

Pointcode pattern composed of 2 × 6 identical grating-dot units.

Fig. 6
Fig. 6

Pointcode pattern created with the one-point two-size five-position method (P, pointcode pattern; H, grating-dot hologram).

Fig. 7
Fig. 7

Grating dots in the pointcode pattern in Fig. 6.

Fig. 8
Fig. 8

Setup used to reconstruct a pointcode image from a pointcode pattern.

Fig. 9
Fig. 9

Pointcode image diffracted from the pointcode pattern in Fig. 6.

Fig. 10
Fig. 10

Gray values of the pixels on the x axis in Fig. 9.

Fig. 11
Fig. 11

Pointcode pattern created with the two-point two-size three-position method (P, pointcode pattern; H, grating-dot hologram).

Fig. 12
Fig. 12

Pointcode image diffracted from the pointcode pattern in Fig. 11.

Equations (5)

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p = n λ [ ( cos α d cos α i ) 2 + ( cos β d cos β i ) 2 ] 1 / 2 ,
θ = tan 1 ( cos α i cos α d cos β d cos β i ) ,
cos α d = x ( x 2 + y 2 + L 2 ) 1 / 2 ,
cos β d = y ( x 2 + y 2 + L 2 ) 1 / 2 ,
cos γ d = L ( x 2 + y 2 + L 2 ) 1 / 2 .

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