In general, the moisture content of the material is different in the center and the surface of the material.
So, it called the Local moisture content, which is the moisture content of any measurement point.
And, it called the Average moisture content, which is the moisture content of the average of the whole material.
By recent innovation, a cheap, high-performance microwave transmission-type measuring instrument came up.
There is a high correlation to the moisture content and the attenuation characteristics of the microwave. (Up to about 30%)
By using characteristics of microwaves transmitted, and measure the material, including the moisture in the core as well as moisture on the surface of the material.
Since the amount of moisture of a penetration part including the central part of material can be measured like a resistance equation or a high frequency type unlike the system which measures moisture of a material list side, a high-precision result is obtained.
Moreover, when move the measurement point, the amount of attenuation is proportional to the moisture content of the site of the material that has passed through can be measured.
By applying this, the moisture gradient inside material could be displayed in the graph, and the average moisture content of a measured region can be displayed now.
Related page:
1-5.Equilibrium moisture content and Critical moisture content – Influence of temperature and relative humidity 
1-7.Drying characteristic curve – Relation between a drying rate and moisture content 
1-3.How to expressions the moisture in the material 
2-3.Moisture Content of the Air 
1-8.Why is the constant drying period. – Moisture movement in wet material. 
1-1.What is drying 
3-5.Balance of the process 
2-11.Dew point and Dew point meter