A system and method includes an infrared camera; a processing unit; and an output unit. The infrared camera is configured to acquire a plurality of infrared images of the device, wherein the plurality of infrared images comprises a first infrared image and a second infrared image acquired a time period after the first infrared image. The processing unit is configured to determine a pixel in the first infrared image with a hottest temperature and determine a pixel in the second infrared image with a hottest temperature. The processing unit is configured to determine a first number of pixels in the first infrared image that have a temperature within a threshold temperature of the hottest temperature of the first infrared image and determine a second number of pixels in the second infrared image that have a temperature within the threshold temperature of the hottest temperature of the second infrared image.