1. A device comprising: one or more computer-readable media; and one or more processors that are coupled to the one or more computer-readable media and that are configured to cause the device to obtain an image, identify pixels in the image that have intensity values that equal or exceed a first intensity threshold in a first color channel, identify a trajectory based on the pixels in the image that have intensity values that exceed the first intensity threshold in the first color channel, identify multiple instances of the trajectory in the image, identify an instance of the trajectory that includes pixels that have intensity values that do not equal or exceed a second intensity threshold in a second color channel, and generate a blur kernel based on the intensity values in the second color channel of the pixels in the instance of the trajectory.