An image gradient refers to the change in intensity or color in an image. It is a mathematical representation that shows how pixel values vary across the image. Gradients are essential in image processing as they help identify edges, textures, and other important features by highlighting areas where there is a significant change in brightness. In the context of computer vision, gradients are often calculated using techniques like the Sobel operator or Prewitt operator. These methods apply convolution to the image, resulting in gradient maps that indicate the direction and magnitude of changes. This information is crucial for tasks such as object detection and image segmentation.