The study was conducted by using 2D image processing technique, actual measurements of three dimensions 'a' , 'b' and 'c' mutually perpendicular axes by vernier caliper and actual volume of grain by picnometer during soaking, with an objective of estimation of volume. The study revealed that; (1) the ratio of instantaneous size to initial size a/a0, b/b0 and c/c0 change with moisture content have a significant disproportion as moisture content increases. (2) The ratio 'b/a' and 'c/a' changes with moisture content have 3 periods: constant, falling, and equilibrium. (3) Shape factor has linear relationship with moisture content, and temperature is insignificant. (4) The product of the sizes 'a', 'b' and 'c', that is volume of the circumscribing rectangular box, closely estimates measured volume of grain based on circumscribed theoretical volume within r2=0.90. (5) Specific volume (abc) and actual specific volume have linear relationship with moisture content, and temperature is insignificant. (6) Actual dry solid density of soybean can be extrapolated from specific volume-moisture content relation, and evaluated as 1.36 (g/cm3). Difference in initial moisture content is insignificant. (7) Image pixels raised to the power of 1.5 modified by shape factor can estimate measured volume within r2=0.90.