An image capturing device capable of simplifying characteristic value sets of captured images and a control method thereof. The image capturing device comprises a characteristic conversion module, a data storage module, a characteristic simplification module, a template storage module and a recognition module. The characteristic conversion module converts an image captured by the image capturing device into a characteristic image, and the characteristic image includes a group of first characteristic value sets. The data storage module stores a lookup table which comprises second characteristic value sets. The characteristic simplification module performs a simplification process according to the lookup table to produce a simplified group of characteristic value sets. Finally, compares the simplified group of characteristic value sets with the plurality of templates stored in the template storage module to recognize a specific object in the image.