How to Change Image Perspective With GIMP Freeware

GIMP is a powerful image editing program that can be downloaded for free (see Resources below). In this article we will show you how to use the software to change the perspective of an image. Perspective is the way in which objects appear to the viewer based on their physical attributes. When photographing a large building like the one in the example below, the building will appear to be tipping or leaning. Architectural photographers will use view cameras or special lenses to correct this effect. You can correct it quite easily using software, but you may have to adjust the overall size of your image.

Instructions

Difficulty: Moderately Easy

Things You’ll Need:

• GIMP 2.0 running on a PC or MAC computer
• A suitable image for editing

1. Original Image Open your saved file in GIMP. The accompanying image is the Cathedral of Learning on the campus of the University of Pittsburgh. Notice how the building appears to be leaning to the left and backwards. This is due to the distortion of the wide angle lens needed to get the whole building in the photograph.
2. Perspective Control Panel Under the TOOLS, select TRANSFORM TOOLS and PERSPECTIVE. The short cut key is SHIFT plus P. Once you open the tool you will see the transform tool box. Notice the transformation matrix is set to one and zero.
3. Making the Adjustment In this case we will move the tool towards the left to straighten the building. Continue the move until the building looks normal. You will notice the numbers in the transformation matrix change as you move your mouse. Ignore the rest of your picture as you make the adjustment. White space will become part of the image as you make your move. When the perspective seems normal, select TRANSFORM to make the transformation.
4. Image transformed The building looks fine now, but there is some white space in the canvas which was created when you made the transformation. To change this you will need to crop the image.
5. Final Image Use the rectangle select tool to select the part of the image you want to keep. Under the IMAGE tab, choose CROP TO SELECTION to crop out the white space caused by the transformation. The image now looks normal, but it is slightly smaller in size from the cropping.

Tips & Warnings

• Choose images that will benefit from some small cropping.
• Sometimes the image benefits from perspective shift, such as images that illustrate the vanishing point. Two railroad tracks may seem to merge at a point in the background and this effect may actually be beneficial to the photo. Choose your images carefully.
• Always work with copies of your images to preserve your image archive.