A time of flight distance measurement system, comprising: a light emitter; a time of flight sensor comprising: a photosensitive image region (1,50) comprising an array of M by P pixels, where P is a positive integer, arranged to respond to light incident on the photosensitive image region; a storage region arranged not to respond to incident light, the storage region comprising M columns of N storage elements, each column of N storage elements constituting a delay line where the input of each delay line is connected to a corresponding column of P pixels, arranged to transfer data along the M columns of storage from a respective one of the M pixels along column of N storage elements at a transfer frequency Ft, each row of M storage elements storing data captured at the same time; and a readout section arranged to read out data from the M columns of the storage region at a readout frequency Fr; and circuitry for controlling the time of flight sensor to capture image data in the image region and to transfer the captured image data from the M by P pixels of the photosensitive image region along the delay line formed by the M columns of the storage region at the transfer frequency Ft and then to readout the captured image data at the readout frequency Fr different to the transfer frequency, wherein the pixels and the storage elements are charge coupled elements. a light emitter; a time of flight sensor comprising: a photosensitive image region (1,50) comprising an array of M by P pixels, where P is a positive integer, arranged to respond to light incident on the photosensitive image region; a storage region arranged not to respond to incident light, the storage region comprising M columns of N storage elements, each column of N storage elements constituting a delay line where the input of each delay line is connected to a corresponding column of P pixels, arranged to transfer data along the M columns of storage from a respective one of the M pixels along column of N storage elements at a transfer frequency Ft, each row of M storage elements storing data captured at the same time; and a readout section arranged to read out data from the M columns of the storage region at a readout frequency Fr; and circuitry for controlling the time of flight sensor to capture image data in the image region and to transfer the captured image data from the M by P pixels of the photosensitive image region along the delay line formed by the M columns of the storage region at the transfer frequency Ft and then to readout the captured image data at the readout frequency Fr different to the transfer frequency, a photosensitive image region (1,50) comprising an array of M by P pixels, where P is a positive integer, arranged to respond to light incident on the photosensitive image region; a storage region arranged not to respond to incident light, the storage region comprising M columns of N storage elements, each column of N storage elements constituting a delay line where the input of each delay line is connected to a corresponding column of P pixels, arranged to transfer data along the M columns of storage from a respective one of the M pixels along column of N storage elements at a transfer frequency Ft, each row of M storage elements storing data captured at the same time; and a readout section arranged to read out data from the M columns of the storage region at a readout frequency Fr; and circuitry for controlling the time of flight sensor to capture image data in the image region and to transfer the captured image data from the M by P pixels of the photosensitive image region along the delay line formed by the M columns of the storage region at the transfer frequency Ft and then to readout the captured image data at the readout frequency Fr different to the transfer frequency, wherein the pixels and the storage elements are charge coupled elements.