We introduce new transforms for efficient compression of image blocks with directional preferences. Each transform, which is an orthogonal basis for a specific direction, is constructed from an eigen-decomposition of a discrete directional Laplacian system matrix. The method is a natural extension of the DCT, expressing the Laplacian in Cartesian coordinates rotated to some predetermined angles. Symmetry properties of the transforms over square domains lead to efficient computation and compact storage of the directional transforms. A version of the directional transforms was implemented within the beyond HEVC software and demonstrated significant improvement for intra block coding.

中文翻译：

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使用离散方向拉普拉斯本征解的正交方向变换实现超越 HEVC 帧内编码


我们引入了新的变换，可以有效地压缩具有方向偏好的图像块。每个变换是特定方向的正交基，是根据离散方向拉普拉斯系统矩阵的特征分解构造的。该方法是 DCT 的自然扩展，用旋转到某些预定角度的笛卡尔坐标表示拉普拉斯算子。方形域上变换的对称特性导致方向变换的高效计算和紧凑存储。方向变换的一个版本在 Beyond HEVC 软件中实现，并展示了块内编码的显着改进。