TransmAvrg, TransmSD

Menu:   Measure > Parameters

Script:   SelectParam ("TrahnsmAvrg", "TransmSD")

Select these parameters to compute the optical transmission within the objects. The transmission measures the relative amount of light that passes through the material. At a given point of the image the transmission is defined as the ratio of the pixel intensity divided by the average background intensity:


The average background intensity of the image is established during the Background correction procedure that should be performed prior to the transmission measurements. If no background correction was done, the maximum intensity value for the current image type is used in calculations. If the image is of the floating point type, the non-corrected background is assigned the value of 1.

The gray values of pixels can optionally be scaled by using the Intensity calibration in order to compensate for the non-linearity of the imaging tract.

TransmAvrg returns the average transmission within the object.

, where N is number of pixels within the object


TransmSD returns the standard deviation of the transmission within the object:

,

In the Field Measurements the parameters are calculated for the whole phase rather than for separate objects.

Note – the transmission parameters could be used to measure the reflectivity which is defined as the ratio between the amount of light reflected divided by the total amount of incident light. In this case TrasmAvrg returns the average reflectivity within the object and TransmSD returns the standard deviation of the reflectivity.