An apparatus includes a welding torch, a laser capable of projecting a beam towards a seam on a surface, a camera directed towards the surface, a memory, and a processor. The processor receives an image of the surface from the camera. Next, the processor determines, based on the reflection of the laser beam from the surface, a vertical distance from the torch to the seam. The processor adjusts the brightness and contrast of the image, applies a gamma correction, and applies at least one gradient filter to the image to produce a new image. Next, the processor determines a horizontal location of the seam in the new image, which it uses to determine a horizontal distance from the torch to the seam. Based on the vertical and horizontal distances from the torch to the seam, the processor adjusts a vertical and a horizontal position of the torch.