The stone640 dataset contains 175 images, while the stonelion640 dataset contains 123 images.
The two datasets are created by the smart phone Xiaomi Note Pro, using the Camera FV-5 app. The image resolution is 640 * 480, focal length is 3.800mm. Xiaomi Note Pro is equipped with Sony IMX 214 image sensor, thus the CCD size is 5.867 mm (1/3.06"). More information about the sensor is available at https://en.wikipedia.org/wiki/Exmor.