A Laplacian filter is a type of image processing technique used to enhance edges in images. It works by calculating the second derivative of the image, highlighting areas where there are rapid changes in intensity. This makes it effective for detecting edges and fine details. The filter is often applied in the context of computer vision and image analysis. By emphasizing edges, the Laplacian filter can help improve the performance of other algorithms, such as object detection and image segmentation, making it a valuable tool in various applications.