Discrete tomography reconstructs an image of an object on a grid from its discrete projections along relatively few directions. When the resulting system of linear equations is under-determined, the reconstructed image is not unique. Ghosts are arrays of signed pixels that have zero sum projections along these directions; they define the image pixel locations that have non-unique solutions. In general, the discrete projection directions are chosen to define a ghost that has minimal impact on the reconstructed image. Here we construct binary boundary ghosts, which only affect a thin string of pixels distant from the object centre. This means that a large portion of the object around its centre can be uniquely reconstructed. We construct these boundary ghosts from maximal primitive ghosts, configurations of \(2^N\) connected binary (\(\pm 1\)) points over N directions. Maximal ghosts obfuscate image reconstruction and find application in secure storage of digital data.

离散层析成像从物体的离散投影沿相对较少的方向重建其图像。当得到的线性方程组的系统不确定时，重建的图像不是唯一的。鬼影是有符号像素的阵列，在这些方向上的投影和为零；它们定义具有非唯一解的图像像素位置。通常，选择离散投影方向以定义对重建图像影响最小的重影。在这里，我们构造了二进制边界重影，它只影响远离对象中心的一小串像素。这意味着可以围绕对象中心唯一地重建对象的大部分。我们从最大原始幻影，\（2 ^ N \）的配置构造这些边界幻影在N个方向上连接的二进制（\（\ pm 1 \））点。最大的重影混淆了图像重建，并在数字数据的安全存储中找到了应用。