影像截取器，或称：影像截取卡，是从模拟视频信号或数字视频串流中，抓取连续之数字静态画格（frame）的电子设备。此类设备常见于电脑视觉系统中，画格以数字的形式被截取，而产生之数字信号直接或经压缩过再显示、保存或发送至其他设备。

早期的影像截取器因内存的限制只能保存单张影像画格，故得其名。今日的截取器普遍能保存多张画格，并可即时的使用压缩算法如 JPEG 压缩影像。许多应用上的技术需求（如雷达微波截取、工程制造与远程导航等）促使影像截取器朝向「高画格速率」、「高分辨率」的发展。

A frame grabber is an electronic device that captures (i.e., "grabs") individual, digital still frames from an analog video signal or a digital video stream. It is usually employed as a component of a computer vision system, in which video frames are captured in digital form and then displayed, stored or transmitted. Early frame grabbers typically had only enough memory to store a single digitized video frame, hence the singular "frame" in the device name, whereas modern frame grabbers often can store multiple frames.