Mobile systems including image sensors, methods of operating image sensors, and methods of operating mobile systems

A method of operating a three-dimensional (3D) image sensor, the method comprising:

• performing a first sensing based on a trigger signal to detect proximity of a subject;
• and
• performing a second sensing to recognize a gesture of the subject by acquiring distance information for the subject when a result of the first sensing represents that the subject is proximate to the 3D image sensor.

A method of operating an image sensor including a plurality of depth pixels and color pixels, the method comprising;

• performing a first sensing based on a trigger signal to detect proximity of a subject;
• and
• performing at least one of a second sensing to recognize a gesture of the subject by acquiring distance information for the subject and a third sensing to acquire color image information of the subject when a result of the first sensing represents that the subject is proximate to the image sensor.

-32. (canceled)