Defects inspection of the solder bumps using self reference technology in active thermography

•We proposed a method for reducing the impact of emissivity unevenness and heating non-uniformity.•The method using the self reference technology is based on the source distribution image.•Three thermograms captured right after heat pulse are averaged to create SDI.•For the missing bump the summation of thermal difference is no more than 14K.•It is effective using the method to identify the defects in active infrared test.