  This paper proposes a novel algorithm for multi-focus thermal image fusion.
The algorithm is based on local activity analysis and advanced pre-selection of
images into fusion process. The algorithm improves the object temperature
measurement error up to 5 Celsius degrees. The proposed algorithm is evaluated
by half total error rate, root mean squared error, cross correlation and visual
inspection. To the best of our knowledge, this is the first work devoted to
multi-focus thermal image fusion. For testing of proposed algorithm we acquire
six thermal image set with objects at different focal depth.
