ToF camera measures the distance from the object to the camera by measuring the time from when the light is emitted to when it is reflected back to the camera through the object. ToF camera uses the most direct measurement method for depth imaging, obtains better depth information with the smallest computing resources, and realizes the construction of depth scenes with a higher frame rate. According to its basic principles, ToF depth cameras, like lidars, can also be divided into pulsed TOF (P_TOF) and continuous wave modulation TOF (CVM_TOF). P_TOF transmits light pulses (generally invisible light) to the observed object, and then receives the light pulses reflected from the object, and calculates the distance of the measured object from the camera by detecting the flight (round-trip) time of the light pulses; CVM_TOF sends out A beam of modulated continuous light is used for ranging by measuring the phase difference between the return and transmission of the light and inverting the time-of-flight of the light. If you want to obtain accurate depth measurement data, at least the following problems need to be solved.
What if the tof camera is not accurate enough? The easiest way to do this is to increase the integration time or make multiple measurements.
ToF camera ranging needs to convert the photoelectric analog signal into a digital signal for processing. In the ADC process, the analog signal is equivalent to rounding at the minimum resolution. This process will inevitably introduce some noise. The 1.1V analog signal may only be recognized as a 1V signal, with an error of 10%, and an analog 10.1V signal may only be recognized as a 10V signal after AD, with an error of 1%, and a 100.1V signal is recognized as 100V, with an error of 1 ‰. Therefore, the AD conversion process will introduce noise and errors especially when the signal strength is relatively low. In addition, the relationship between the signal-to-noise ratio SNR of the ToF camera and the integration time t is usually SNR∝1/√t, so increasing the integration time and improving the signal strength may be an effective solution.
