2013-01-15 14.20.23 from wayne k on Vimeo.

Bezel correction is the term used to accommodate for the molding around the screens glass display that holds the panel together. Every screen manufacture has different size bezel for their screens. 

The size of the bezel can be different on the top, bottom and sides of the screen. 

If the screens are arranged directly beside each other, the media will appear to “skip” the bezel region of the screen possibly distorting the media. 

For example, without bezel correct a round object in media, spanning multiple screens may not appear round but will have extra space making the object larger. The bezel correction can compensate for this effect by cutting out the video “behind” the bezel, causing a round object to actually appear round.

The total canvas size should also include any correction for the size of the screen bezels. Since all the measurements of the canvas are in pixels, the number of pixels used by the bezel will have to be calculated.

Bezel correction is only required on the “inside” portions of the screens as the content will usually not extend past the outside portion of the screens into the outside bezel.

To add Bezel correction, add spaces between the screens that are the same size as the bezel converted to pixels rather than inches.

Calculating the Bezel size in Pixels
To calculate bezel correction in the horizontal direction, consider the following:
Let the width of the screen (glass) be X inches.
Let the resolution of the screen in the horizontal direction is W pixels.
Let the bezel size is B inches.
The number of pixels in one inch of screen is N = W/X.
The bezel width in pixels = N * B = W * B / X

In words, bezel correction in pixels = (screen width in pixels) * (bezel width in inches) / screen (glass) width in inches.
Similar considerations can be undertaken for the vertical direction.