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数字信号的一个最大优点就是处理上的灵活性。在数字图象信号传递过程中常常由于一些特殊的需要,要求对图象进行放大(Zooming)和缩小(Scaling)处理。例如,在 VCD 中常常需要对高清晰度静止图象的某部分加以扩大,即所谓 Zooming 技术。Zooming 是对数字图象信号进行点线重复扫描的一种处理方法。但是,单纯的扩大会使图象的轮廓变粗,直线及曲线会产生锯齿。为了避免这种现象,通常采用插补法(Interpolation)来改善图象质量。例如,在垂直方向的两行中插入由相邻两行各对应取样点的平均数据作成的新的一行;在水平方向相邻两象素问也同样取其平均值作插补值。经这样放大的图象可消除锯齿,获得彩色线条渐变的最佳圆滑。反之,进行消点取样可进行缩小(Scaling)。例如,
One of the biggest advantages of digital signals is processing flexibility. In the digital image signal transmission often due to some special needs, require the image zooming (Zooming) and Scaling (Scaling) processing. For example, it is often necessary to enlarge a portion of a high definition still image in VCD, the so-called Zooming technique. Zooming is a processing method for dot-line repetitive scanning of digital image signals. However, a simple enlargement will make the outline of the image thicker and the straight lines and curves will be jagged. In order to avoid this phenomenon, interpolation is usually used to improve the image quality. For example, a new line made up of the average data of the corresponding two sampling points in two adjacent lines is inserted in two lines in the vertical direction. Similarly, the average of two adjacent pixels in the horizontal direction is used as the interpolation value. The zoomed-in image is thus eliminated, resulting in the best smoothness of color line gradients. Conversely, taking a spot can be scaled down (Scaling). E.g,