A new electrical resistance tomography (ERT) system, based on the bi-directional current pulse technique, is developed. Polarization effects at the electrodes are eliminated. During each half cycle of the excitation process, direct current (DC)is used as the excitation source and filtering is not needed. Moreover, using optimized data collection protocol, the number of current injections for a 16-electrode system is reduced to 14 for 104 independent readings of an image. Experimental results showed that the system is effective using the sensitivity coefficient algorithm for image reconstruction.