In this paper the implementation of the surface stiffness mapping method with the dynamic measurement mode of atomic force
microscopy (AFM) is presented. As the measurement of the higher harmonics of the cantileverís torsional bending signal is performed,
we are able to visualize non-homogeneities of the surface stiffness. In order to provide signal processing with the desired sensitivity and
selectivity, the lock-in amplifier-based solution is necessary. Due to the presence of several useful frequencies in the signal, the utilization
of several simultaneously processing channels is required. Therefore the eight-channel software-based device was implemented. As the
developed solution must be synchronized with the AFM controller during the scanning procedure, the real-time processing regime of the
software is essential. We present the results of mapping the surface stiffness and the performance tests results for different working conditions
of the developed setup.