9. Changing the Aspect Ratio for Borderless Printing

In the case of borderless printing, some cropping or trimming of the image borders is necessary; that is, it is necessary to discard (not print) parts of the image. The reason for this is the nonconformity of the aspect ratios of the original image produced by the image capturing device and final hard copy. In the first part of the chapter, a smart trimming method is proposed as an effective tool for changing the original aspect ratio by eliminating strips from the top and bottom (and/or left and right) sides of the image. The word “smart” means that such trimming will not corrupt the main objects in the photo. In the second part of Chapter 9, an original approach for matching the aspect ratio of a digital photo for borderless printing by complementing it with fragments extracted from the same photo is described. This approach comprises analysis of side strips of the source photo to estimate the possibility of its building up without visible artefacts; complementing one or two opposite sides of the photo to match the desired aspect ratio; and additional processing of complements to make the resulting photo look more natural. The proposed algorithms can be applied to colour, greyscale, or sepia-effect photos.