Depth sensing apparatus and method

A depth sensing method, comprising:

• resetting, to a reference voltage value, a voltage of each of a first floating diffusion node and a second floating diffusion node of a sensor pixel for a first time period;
• controlling the first floating diffusion node to store a voltage of a photodiode in a first phase interval for a second time period, and controlling the second floating diffusion node to store the voltage of the photodiode in a second phase interval for the second time period;
• and
• calculating a difference between the voltage of the first floating diffusion node and the voltage of the second floating diffusion node for a third time period.

A depth camera having a depth sensing apparatus, the camera comprising:

• a light emitter to emit light according to a control signal;
• a sensor pixel including a photodiode, a first floating diffusion node and a second floating diffusion node;
• a controller to reset, to a reference voltage value, a voltage of each of the first floating diffusion node and the second floating diffusion node for a first time period, to control the first floating diffusion node to store a voltage of the photodiode in a first phase interval for a second time period, and to control the second floating diffusion node to store the voltage of the photodiode in a second phase interval for the second time period;
• and
• a calculator to calculate the depth value by calculating a difference between the voltage of the first floating diffusion node and the voltage of the second floating diffusion node for a third time period.

A depth sensing method in a depth sensing camera having a light emitter, a sensor pixel including a photodiode, a first floating diffusion node, a second floating diffusion node, and a controller, the depth sensing method comprising:

• resetting, for a first time period, a voltage of each of the first floating diffusion node and the second floating diffusion node;
• storing a voltage of the photodiode in a first phase interval in the first floating diffusion node for a second time period;
• storing the voltage of the photodiode in a second phase interval in the second floating diffusion node for the second time period;
• storing the voltage of the first floating diffusion node in a sampling capacitor for a first portion of a third time period;
• transferring the voltage of the first floating diffusion node to a feedback capacitor;
• storing the voltage of the second floating diffusion node in the sampling capacitor for a second portion of the third time period;
• and
• calculating a difference between the voltage of the first floating diffusion node and the voltage of the second floating diffusion node for the third time period, thereby eliminating an effect of background light received by the photodiode.

A depth camera having a depth sensing apparatus, the camera comprising:

• a light emitter to emit light according to a control signal;
• a sensor pixel including a photodiode, a first floating diffusion node and a second floating diffusion node;
• a controller to eliminate distortion of a depth value occurring due to background light by controlling timing of light emitted from the light emitter by way of the control signal to perform active depth sensing and to control the sensor pixel by storing voltages of the photodiode at different phase intervals and at different time periods in the first and second floating diffusion nodes;
• and
• a calculator to calculate the depth value by calculating a difference between a voltage of the first floating diffusion node and a voltage of the second floating diffusion node for a predetermined time period, thereby eliminating an effect of background light received by the photodiode.