The CalTech Calibration Toolbox can output the corrected images that you gave it. This is a nice tool because you can see if you calibration parameters are correct. Below is an example of the before and after calibration images.

The image on the left is the original image. It was chosen because you can easily see the high levels of distortion on the grid. The image on the left is what was outputted from the toolbox. The lines on the grid have been straightened which is a good sign that the toolbox parameters are correct.