Distance measurement device

A distance measuring device configured to obtain a distance to an object by a time-of-flight method, the device comprising:

• a light source unit configured to emit modulated light;
• a sensor unit including a photosensitive region configured to generate a charge in accordance with incident light, an accumulating region configured to accumulate the charge generated in the photosensitive region, a transfer electrode provided between the photosensitive region and the accumulating region, and a reset switch provided between the accumulating region and a reset potential, and;
• a processing unit configured to calculate the distance by controlling emission timing of the modulated light and controlling the sensor unit,
• wherein the processing unit
• causes the light source unit to emit the modulated light in one or more emission periods in a plurality of charge transfer cycles within a frame period from connection of the accumulating region to the reset potential to next connection of the accumulating region to the reset potential by controlling the reset switch, and increases the number of emission periods per charge transfer cycle within the one frame period,
• accumulates the charge generated in the photosensitive region into the accumulating region by controlling a voltage applied to the transfer electrode in one or more transfer periods synchronized with the one or more emission periods,
• obtains, from the sensor unit, a plurality of read values corresponding to a charge amount accumulated in the accumulating region at an alternate point with the plurality of charge transfer cycles in each of a plurality of read cycles corresponding to each of the plurality of charge transfer cycles, and
• calculates the distance based on the plurality of read values.