Method and system to determine distance using time of flight measurement comprising a control circuitry identifying which row of photosensitive image region has the captured image illumination stripe

A time of flight distance measurement system, comprising:

• a light emitter (2,3) arranged to emit a pulsed fan beam for illuminating a remote object with a pulsed illumination stripe;
• a time of flight sensor (9) comprising:
• a photosensitive image region (8) comprising an array of M columns of P rows of pixels, where both M and P are positive integers greater than 2, arranged to respond to light incident on the photosensitive image region (8);
• a storage region (10) arranged not to respond to incident light, the storage region comprising M columns of N storage elements, arranged to transfer data along the M columns of storage from a respective one of the M pixels along column of N storage elements;
• and
• a readout section (11) arranged to read out data from the M columns of the storage region;
• and
• circuitry (1) for controlling the time of flight sensor (6) to capture image data of the pulsed illumination stripe along a row of pixels and to transfer the captured image data to the storage section;
• wherein the circuitry is arranged to operate the time of flight sensor in a self-calibration step including capturing the image illumination stripe on the photosensitive image region (8), then reading out the data from the image region (8) via the storage region (10) and the readout section (11) and identifying which row of the photosensitive image region has the image illumination stripe;
• and
• in a distance determining step including determining the distance to the remote object by clocking the image region while capturing the image of the object illumination stripe, reading out the data from the image region (8) via the storage region (10) and the readout section (11) and determining the distance to the object.