1. Computer generated cluster of Gaussian peaks to simulate a typical image. White loops show outlines of peaks as found by BSA.
2. Mesh plot of peak cluster in Fig. 1.

3. Isophotes, or contours of constant intensity, chosen at equal intervals. Setting one threshold would select the peaks inside contours of one intensity. Peaks labeled for reference in text and next caption.

4. Binary images from setting various thresholds for Fig. 1. Thresholds for 4-1 through 4-20 are set to levels illustrating various stages in the BSA. They are shown in increasing order, labeled 1-20, and referred to by this number in the text.
1. No peaks resolved - all included in one blob.
2. Peak f just resolved (just split from parent blob).
3. Peaks e and f both resolved.
4. Peak e just disappearing: it has not split into smaller peaks so its associated blob (resolved somewhere between threshold numbers 2 and 3) is recorded as an 'object'.

5. Peak f just disappearing. Analogously to Peak e, blob representing peak f in Fig. 2 (at threshold 2) is stored as an object.
6. Peak d almost resolved.
7. Peak d resolved.
8. Blob d shrinking, but no splitting has occurred.

9. Peak d just disappearing. Corresponding blob in Fig. 7 recorded as object.
10. Peaks a, b and c are all that remain, but none are yet resolved.
11. Peak c almost resolved.
12. Peak c resolved.

13. Peak c has disappeared. Since it did not split into smaller peaks after being resolved somewhere between thresholds 10 and 11, the appropriate blob is stored as another object.
14.Peaks a and b not yet resolved.
15.Peaks a and b still not yet resolved.
16. Parent blob has just split into blobs a and b.
Both peaks gradually disappear without further splitting in Figs. 17-20, and are kept as the final two objects.

5. Electron diffraction pattern.
a. Fiber with rows of spots and very wide range of spot sizes and intensities.

b. Outlines of spots as found by algorithm.
c). Portion of b to upper right of center spot, compressed to 5 gray levels (darkest level not visible). a-arrow: 4 pixel spot. b-arrow: larger spot not selected because number of gray levels is too small (see text).

6. Electron diffraction pattern.

a. All spots are hard to resolve automatically (although they are easily resolved by eye) because of wide range of spot sizes and brightness.

b. Rectangles surrounding individual spots as found by BSA.

7. Electron diffraction pattern.

a. spots of varying size and brightness.

b. Rectangles outline individual spots. Dots and circles illustrate refined peak locations needed for diffraction pattern analysis (see text). Diffraction patterns are inverted if necessary before applying algorithm so that spots are brighter than background. Areas of circles are equal to areas of corresponding blobs.

8. Electron diffraction pattern.

a. Rings.

b. Outlines of portions of rings for determining beam center position, as found by algorithm. Additional blob in background seen above rings -- to be culled later using shape, size or position.

9. Fluorescein spheres.

a. Light micrograph, fluorescence mode. Rectangles, from algorithm, show sphere locations.

b. Magnification of region of Fig. 9a showing that rectangles from BSA might not touch perceived outlines of objects (highlighted in white).

10. Illustrations showing that one threshold will not resolve all spheres of Fig. 9a.

a. Same as Fig. 9a but shrunk x2.

b. Binary image from lower threshold -- dim spheres resolved but boundaries often not correct. Brighter spheres with close neighbors not resolved.

c. Binary image from higher threshold -- dim spheres missing, some brighter spheres resolved.

d. Binary image from yet higher threshold -- two brightest spheres just resolved, but many dimmer spheres missing.

11. Background image for fluorescein spheres.

a. Greatly enhanced minimum filter (Bright 1987b) of Fig. 9a. Dark squares have twice edge length of filter kernel and are due to dark specks in b.

b. Enhancement of Fig. 9a. Degree of enhancement same as a.

12. Ion microscope aluminum image of inclusions in steel. Outlines as found by the BSA sometimes obscured on print by bright areas. Some inclusions have "holes".

13. Ion microscope Barium image of particles.

a. Image taken with Cameca FFF ion microscope*.

b. Particle outlines as found by BSA.

c. Gradient image of a.

14. Complex agglomerate particle.

a. TEM image.

b. Fig. a with outlines showing regions found by BSA with Amin = 500.

c. Grid superimposed on a. Finest grid mesh shows 10 x 10 pixel squares. Curves show intensity histogram of background region of b. (gray) and of same area of c. (white). Background of b. taken as lower left 100 x 100 pixel area.

d. Image of random numbers to simulate the background noise in b. Dark and light shaded areas show regions found by BSA with Amin = 500.

15. Histogram of blobs for Fig. 14b (see text).

16. BSA regions of particle in Fig. 14, 256 gray level image.

a. Regions selected from Fig. 14b using group A of Fig.15. Amin = 500 pixels.

b. Regions for Amin = 5000 pixels.

c. Regions for Amin = 50 pixels.

17. BSA regions as in Fig. 16, but for 32 gray level image.

a. Amin = 500 pixels.

b. Amin = 5000 pixels.

c. Amin = 50 pixels