The modified DAC version with thermal quadrupoles can be considered an interesting alternative to thermal contrast computations since it provides an automated tool for depth retrieval and eliminates the need of selecting a non-defective area. In practice it is important to have heat stimulus with complex shapes and long durations (several seconds) in order to cover larger inspection areas, enhance thermal contrast between defective and sound areas and increase the depth of inspection inside the material. In this work we present a heat stimulus correction by using the thermal quadrupoles theory and its validation with several heat stimulus shapes and durations.