Abstract: A method of taking pictures for generating three-dimensional image data is disclosed. The method includes continuously illuminating a target object with an environmental light; using an image sensor to receive the light reflected from the target object to generate a first electrical image signal; illuminating the target object with an active light generated from an active light source unit during the period of exposure by the environmental light; using the same image sensor to receive another reflected light to generate a second electrical image signal; using an image processing unit to receive the first and second electrical image signals, convert the first electrical image signal to a two-dimensional image data, and subtract the first electrical image signal from the second electrical image signal to generate three-dimensional depth data; and combining the two-dimensional image data and the three-dimensional depth data to generate the three-dimensional image data.