Infrared thermal devices are widely used in the industrial

medical

military

and other fields and significantly expand the visual perception range of humans. However

infrared thermal videos have low contrast and blurred details

and the subtle variations in these videos are difficult to observe. In this work

we design an amplification method for magnifying the barely seen changes in infrared thermal videos based on Eulerian perspective. Our goal is to reveal temporal variations that are difficult or impossible to be seen with the naked eye and to display these variations in an indicative manner. The proposed method uses an infrared thermal video as input and applies contrast pyramid decomposition to each frame

followed by temporal filtering of the decomposed images. The signals selected by temporal filtering are then amplified to reveal hidden information. The contrast pyramid is then constructed. Finally

noise reduction is performed on the reconstructed images

and the final output is obtained. Corresponding infrared thermal videos were obtained

and experiments were conducted on these videos to magnify the subtle colors and motion variations. For example

the signal from 0.75 Hz to 1 Hz of a profile video was filtered and magnified 100 times as output to augment the color changes in the video. The signal from 100 Hz to 120 Hz of a guitar video was also filtered and then magnified 30 times as output to augment the motion variations in the video. Experiments showed that the proposed method can effectively magnify imperceptible variations in infrared thermal videos. This study demonstrates that imperceptible variations in infrared thermal videos can be magnified and shown to observers in an indicative manner

which is valuable for both military and civil fields.