mmdlith - Detect defects in a microelectronic circuit.

Description: The input image is a gray-scale image of a microelectronic circuit. The relevant objects in this image are vertical metal stripes. These stripes have some irregularities that should be detected. Our procedure takes the residues of a gray-scale closing and filter (by size) the threshold of the residues.

Reading

The input image is read. The image is also displayed as a surface model.

a = mmreadgray('r4x2_256.tif');
mmshow(a);
mmshow(mmsurf(a));

(a)

(mmsurf(a))

Closing

Closing of the image by a vertical line of length 25 pixels. Then subtract it from the original. The sequence closing-subtraction is called closing top-hat. (This could be executed in a single command: c=mmcloseth(a,mmseline(25,90));).

b = mmclose(a,mmseline(25,90));
mmshow(b);
mmshow(mmsurf(b));

(b)

(mmsurf(b))

Subtraction

Subtraction of the closing from the original is called closing top-hat. It shows the discrepancies of the image where the structuring element cannot fit the surface. In this case, it highlights vertical depression with length longer than 25 pixels.

c = mmsubm(b,a);
mmshow(c);
mmshow(mmsurf(c));

(c)

(mmsurf(c))

Thresholding and Area Open

Threshold on the residues image. Elimination of the small objects by area open.

d = mmcmp(c,'>=',50);
Warning: Converting image from scalar to uint8.
e = mmareaopen(d,5);
mmshow(d);
mmshow(e);

(d)

(e)

Final display

Overlay the detected defects over the original image, and over the surface display.

mmshow(a,e);
mmshow(mmsurf(a),e);

(a,e)

(mmsurf(a),e)

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