It is a good idea to take both visible and thermal IR images. Geometric resolution is unbalanced, and each image is sensitive to a different range of the electromagnetic spectrum. To acquire a visible image of a target with a thermal camera, you need to determine or describe the appearance of the target itself. Off-the-shelf digital cameras usually have much higher resolution than thermal imagers, and many users take their pictures with different cameras. However, using the same camera is recommended for visual analysis and automatic image processing. This work will showcase a method for correcting both radial and de-centering lens distortion based on straight lines. Afterwards, registration of both visible and thermal imagery is easily carried out for planar patches by means of a projective transformation. Results obtained from different real scenarios support the methodology and show how beneficial it is, independent of the camera used.