1. An apparatus for generating a thermal image regarding a target object, the apparatus comprising: a memory configured to store a first thermal image; a first sensor configured to measure a temperature of the target object; a second sensor configured to measure a distance to the target object; a third sensor configured to detect a movement of the thermal image generating apparatus; and a controller configured to: generate a second thermal image based on temperature information received from the first sensor, distance information received from the second sensor, and movement information received from the third sensor, and generate a third thermal image based on the first thermal image and the second thermal image.