[mmLabel] [Up] [mmGrain] Measurements

mmBlob
Blob measurements from a labeled image.

Synopsis

Image mmBlob ( const Image& fr , const String& measurement , const String& option = "image" );

Input

fr Image [ Gray-scale (uint8 or uint16) image ]

Labeled image.
measurement String

Choice from 'AREA', 'AREA32', 'CENTROID', or 'BOUNDINGBOX'. The 'AREA32' option is similar to 'AREA' except that it returns an int32 image.
option String

Output format: 'image': results as a binary image; 'data': results a column vector of measurements.

Default: "image"

Output

y Image [ Gray-scale (uint8 or uint16) or binary image ]

Description

Take measurements from the labeled image fr. The measurements are: area, centroid, or bounding rectangle. The parameter option controls the output format: 'IMAGE': the result is an image; 'DATA': the result is a double column vector with the measurement for each blob. The region with label zero is not measured as it is normally the background. The measurement of region with label 1 appears at the first row of the output.

Examples

unsigned char fr_raster[] = { 1,1,1,0,0,0,1,1,1,0,0,2,1,1,1,0,2,2 };
Image fr(6, 3, 1, "uint8", (char *)fr_raster);
printf("image:\n%s", (char *)fr.str());
Image f_area = mmBlob(fr, "area");
printf("area:\n%s", (char *)f_area.str());
Image f_cent = mmBlob(fr, "centroid");
printf("centroid:\n%s", (char *)f_cent.str());
Image f_bb = mmBlob(fr, "boundingbox");
printf("boundingbox:\n%s", (char *)f_bb.str());
Image d_area = mmBlob(fr, "area", "data");
printf("area:\n%s", (char *)d_area.str());
Image d_cent = mmBlob(fr, "centroid", "data");
printf("centroid:\n%s", (char *)d_cent.str());
Image d_bb = mmBlob(fr, "boundingbox", "data");
printf("boundingbox:\n%s", (char *)d_bb.str());


image:
      1   1   1   0   0   0 
      1   1   1   0   0   2 
      1   1   1   0   2   2 
area:
        9     9     9     0     0     0 
        9     9     9     0     0     3 
        9     9     9     0     3     3 
centroid:
    0 0 0 0 0 0 
    0 1 0 0 1 0 
    0 0 0 0 0 0 
boundingbox:
    1 1 1 0 0 0 
    1 0 1 0 1 1 
    1 1 1 0 1 1 
area:
        9 
        3 
centroid:
        1     1 
        4     1 
boundingbox:
        0     0     2     2 
        4     1     5     2

Area Transform

Image f2 = mmReadgray("blob3.tif");
Image fr2 = mmLabel(f2);
Image g = mmBlob(fr2, "area");
mmShow(f2);
mmShow(g);

f2 g
Centroids

Image f3 = mmReadgray("blob3.tif");
Image fr3 = mmLabel(f3);
Image centr = mmBlob(fr3, "centroid");
mmShow(f3, mmDil(centr));

f3, mmDil(centr)
Bounding Box

Image f4 = mmReadgray("blob3.tif");
Image fr4 = mmLabel(f4);
Image box = mmBlob(fr4, "boundingbox");
mmShow(f4, box);

f4, box
Large area

Image f5(500, 500, 1, "uint8", 0.0);
Image img = mmFrame(f5, 100, 100, 0, 0, 255);
img.putpixel(450, 450, 0, 255);
Image lbl = mmLabel(img);
Image area = mmBlob(lbl, "AREA32", "DATA");
printf("area:\n%s", (char *)area.str());


area:
     90000 
         1

See also

mmLabel Label a binary image.
mmGrain Gray-scale statistics for each labeled region.
mmLabelflat Label the flat zones of gray-scale images.
mmStats Find global image statistics.
mmDrawv Superpose points, rectangles and lines on an image.
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