Use the blobber tool is used for segmenting images into objects of interest, such as particles. Then use the Blob Tool to measure descriptive parameters for each particle, such as area, average brightness, centroid.
Info & Mask button on threshold slider
Numbers to lower right on the threshold slider:
The numbers to the lower right show the numeric values of the thresholds used for making masks, blobbing. If these are 0 - 0, the image was probably made with the edit commands, and has not yet been scaled. Scale appropriately (Scale / linear) and the slider should work.
11/28/01 Note - the numeric threshold values do not correspond exactly to the red areas of the image - they are often 1 intensity unit off up or down. The threshold numbers are correct - not the red areas . This is a bug I have not yet been able to fix. In case of questions, check the thresholds using Make Mask above.