how to evaluate filtered result of grayscale images

Sir, here I filtered grayimage using mean,median,gaussian,wiener filter but i dont know how to measure filtered results. In one research paper filtered result were mea-sured by calculating their TV values, so my question is how to calculate TV values. the following table specifies TV values those are from reserach paper.

Before Filtering	After filtering
	                Median	Mean	Wiener	Gaussian
TV	2403.0	        1121.0	1315.2	1124.3	1607.3

Table3.1: TV values comparison

filtered results were further mea-sured by calculating their TV