数字变焦 meaning in English

digital zoom

Does this camera have optical or digital zoom
这架相机使用的是光学变焦还是数字变焦？
Optical zoom actually gets a closer shot , while digital zoom essentially just crops an image tighter
光学变焦可以真正得到一个更近的镜头，而数字变焦基本上只是把图像裁切得更紧凑。
In image enhancing aspect , it studies medium filtering algorithm ~ vector filter and image sharpen algorithm . according to the characteristic of digital sampling , a new image sharpen algorithm is given , and it is more effective . in image compressing aspect , it mainly studies the jpeg algorithm
在图像增强方面，主要研究了中值滤波算法、矢量滤波算法、锐化算法以及两种数字变焦算法，并根据数码相机采样的特点，提出了一种更适合于数码相机的锐化算法，取得了较好的效果：在图像压缩方面，主要研究了jpeg压缩标准及顺序算法实现，并将这些算法用于软件开发中。