Novel method for analysis of printed circuit images

Mandeville, Jon R.

doi:10.1147/rd.291.0073

Cited by 67 publications

(11 citation statements)

References 9 publications

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“…Therefore, hybrid approaches are able to detect various defect types in different sizes, inspect the basic dimensions, and achieve better identification results among the existing inspection systems. However, hybrid methods also mean greater computational efforts, and suffer from rotational error and noise effects [9,10,11,16].…”

Section: Introductionmentioning

confidence: 99%

A case study: passive component inspection using a 1D wavelet transform

Yeh

Shen

2003

The International Journal of Advanced Manufacturing Technology

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This paper exploits a wavelet-based scheme to inspect the surface defects and basic dimensions of 0805 Multi-layer Ceramic Chip capacitors (MLCC) using machine vision. The image of a passive component is initially processed to show only two solder plates (terminations). Then, the covariance matrix eigenvector for each boundary point generates the 1D h-p representation to describe the angle variations at the boundaries of each termination. The 1D h-p representation is further decomposed directly by a one-dimensional wavelet transform (1D WT). Since a single corner (an intersection of two boundary edges) and the jag corners (the surface defects) are local deviations on termination boundaries, their locations are represented as intensive and have a highly fluctuated wavelet energy at the 1st detail scale. Concerning a 0805 MLCC type of passive component, the surface defects and single corners on termination boundaries can be captured by appropriate thresholds (e.g., in wavelet energy). The basic dimensions of a passive component are simply the direct distance between located single corners. Real 0805 MLCCs are testing samples to evaluate the performance of the proposed approach. Experimental results show that the proposed method achieves a precise identification of the surface defects and measurements for basic dimensions. The proposed approach is invariant with respect to the orientation, easy to implement and free from a primitive-matching process. Therefore, it is especially suitable for various types of passive components that are similar to the 0805 MLCC in small-batch production.

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Section: Introductionmentioning

confidence: 99%

A case study: passive component inspection using a 1D wavelet transform

Yeh

Shen

2003

The International Journal of Advanced Manufacturing Technology

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“…Since center to center distance estimates between connected pads will be skewed if the traces are not removed, the second preprocessing stage consists of eroding away the traces to leave behind an image consisting exclusively of features to be inspected. The erosion operation [3,7] is a siml)le morphological process which reduces the object by one pixel thickness over its entire perimeter. This operation is performed repeatedly until all traces ate completely eroded.…”

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confidence: 99%

<title>Machine vision inspection of component footprints in PCB artwork</title>

Krishnan

Sommer

1992

Applications of Artificial Intelligence X: Machine Vision and Robotics

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Abstt'act. A new iiiiited circuit boaicI (PCB) inspection scheme designed to peifoim automated iIlSI)eCtiofl of C0fl11)Ofleflt sites is pi'eseiitecl. A digitized illiage of the artwork for a board is stored after digitization via a scanner (300 dots per inch) in a TIFF (Tag Image File Format) file. At inspection time, after reading in the compressed foiiiiat TIFF file and decoding the compressed ilnage, the PCB is gra)11ica11y displayed oh a PC SCFCCfl t()ge(hcr vitIi a coinnianci menu. The user is then taken though a stlies of incnu-d ii yen coin naiid t .) ul t inately check t he dimensions of centerto-cent er distan(2c l)et ween holes and Ikls f:i e1t nic c()lIIpolleLlts on the PCB. The significance of this research i in lw aclapt.atioit of the LIN1(.)N-FINJ) I)1oce(1u1e to develop a robust algorithm t 1) segineilt an i iilage i u t o 111j)C)LCt1t cI)Jce t S hi (1 liaclgiouncL t 0 facili tat e dimensional analysis and inspection of t lie ut voik * Mechanical lngi neering, Urn versit v f Nlai'y laud Halt inure Counts', Cat unsville, MD 21228. Mechanical Engineeting. Peimnsvlvaiiia State tiiiiveisitv.

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“…Each of them has its limitations and advantages. Recently, several authors have described algorithms which integrate both the reference-comparison and the design-rule methods [1][2][3][4].…”

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confidence: 99%