mmdfabric
Detection of vertical weave in fabrics.

The image to be processed is read.

a = mmreadgray('fabric.tif');

mmshow(a);

a

A sequence of dilations (by a disk and two line segments) is applied to enhance the white stripes

b = mmdil(a,mmsedisk(4));

c = mmdil(b,mmseline(25,90));

d = mmdil(c,mmseline(25,-90));

mmshow(d);

d

The markers are the regional minima with contrast 25.

e = mmhmin(d,25);

f = mmregmin(e);

mmshow(f);

f

Watershed of the original image from the dark stripes markers just created. Show the result overlayed on the original image.

g = mmcwatershed(a,f);

mmshow(a,mmdil(g));

a,mmdil(g)

Create a new marker by taking the union of the dark markers and the watershed lines just created. The gradient of the original image is computed.

h = mmunion(g,f);

i = mmgradm(a);

mmshow(h);

mmshow(i);

h	i

The watershed of the gradient of the original image, taking the marker just created, gives the extend of the white regions.

j = mmcwatershed(i,h,mmsebox);

mmshow(a,j);

a,j

The watershed regions area computed. The area of each watershed regions is measured and displayed.

k = mmcwatershed(i,h,mmsebox,'REGIONS');

mmlblshow(k,'border');

l = mmblob(k,'area');

mmshow(l);

k,'border'	l

To select only the fabric spacing, select the regions with small area (less than 2000). Label the narrow regions.

m = mmcmp(l,'<=',2000);

Warning: converting image from scalar to uint16

mmshow(m);

n = mmlabel(m,mmsebox);

mmlblshow(n,'border');

m	n,'border'

Compute the area of each region and plot them. Also display the original image for illustration. From the plot, we can notice that the two rightmost weave spacing are significantly larger than the others.

mmshow(a);

o = mmblob(n,'area','data');

bar(double(o));

a	o