Count Particles in Buffer

This option will count the number of particles falling within the tracking window in a buffer to which an image has been acquired previously. This offers a convenient way of checking the location parameters and/or counting particles. Note that the background is NOT subtracted from the image, nor are any filters applied (except that if single field sample spacing has been specified then the odd lines will be selected).

A copy of the buffer on which particles are to be located is made in buffer 0. Each particle is marked on this copy with a symbol as it is found. Different symbols are used for different particle types as detailed below:

           +       Normal particle satisfying upper threshold
                  Elliptical particle satisfying upper threshold
           þ       Large particle satisfying upper threshold
           .       Small particle satisfying upper threshold

           x       Normal particle satisfying lower threshold
                  Elliptical particle satisfying lower threshold
           .       Small particle satisfying lower threshold

Count particles in which buffer ?

This entry specifies the buffer containing the image of the particles to be counted. The specified buffer will be made the current output buffer.

Mark particles on copy of buffer ?

If yes (<Y>), then a copy of the buffer on which particles are to be located is made in buffer 0. Each particle is marked on this copy with a symbol as it is found. Different symbols are used for different particle types as detailed below:

           +       Normal particle satisfying upper threshold
                  Elliptical particle satisfying upper threshold
           þ       Large particle satisfying upper threshold

           x       Normal particle satisfying lower threshold
                  Elliptical particle satisfying lower threshold. This
                   diamond is smaller than that for upper threshold elliptical
                   particles.
           .       Small particle satisfying lower threshold

Number of normal particles : ### Number of faint particles : ###, ### of which are small Number of elliptical particles : ### Number of large particles : ### ==================================== Total number of particles : ###

Number of blobs rejected : ### % of blobs considered particles: ###.## Press any key to continue ... On completion the counts will be displayed. The Total number of blobs is the count of all the regions or blobs satisfying the threshold criteria within the tracking window. For a blob to be considered as a particle, it must also satisfy the geometric and other intensity criteria. The number of normal particles is the number of particles satisfying the more stringent threshold, while the number of faint particles is the number satisfying the less stringent threshold. The number of elliptical and large particles is the number of "second particles generated" in response to a large size or ellipticity. Elliptical and large blobs produce one normal or faint particle, and one "second" particle. The total number of particles is the sum of the normal, faint, elliptical and large particles and represents the number which would be included in the tracking process. The % particles gives the percentage of the blobs found which resulted in a particle (elliptical and large particles are counted only once).

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DigImage User Documentation

Stuart Dalziel, last page update: 19 February 1996