Distance-image-measuring apparatus and distance-image-measuring method

A distance image measuring apparatus comprising:

• a light source configured to generate pulsed light;
• a light source controller configured to control the light source so that the light source repeatedly generates the pulsed light with a first duration within a period of one frame;
• a pixel circuit part including a photoelectric conversion region configured to convert light into charge, first to M-th (M is an integer equal to or greater than 3) charge readout regions provided in proximity to the photoelectric conversion region and apart from each other, and first to M-th control electrodes provided in correspondence to the photoelectric conversion region and the first to M-th charge readout regions, for applying first to M-th control pulses for charge transfer between the photoelectric conversion region and the first to M-th charge readout regions;
• a charge transfer controller configured to apply the first control pulse to the first control electrode during a second duration, the second duration being equal to or longer than the first duration in correspondence to the generation of the pulsed light by the light source controller, and then, sequentially apply the second to M-th control pulses to the second to M-th control electrodes during the second duration;
• a circuitry configured to read out voltages of the first to M-th charge readout regions of the pixel circuit part as first to M-th detection signals after the application of the first to M-th control pulses by the charge transfer controller and
• configured to repeatedly calculate a distance on the basis of the first to M-th detection signals,
• wherein the circuitry calculates a sum value of signal components of charge generated from the pulsed light other than background light in the first to M-th detection signals on the basis of the first to M-th detection signals, calculates the distance from the first to M-th detection signals using a predetermined calculation equation when the sum value of the signal components exceeds a first predetermined threshold value, and invalidates the calculation of the distance when the sum value of the signal components does not exceed the first threshold value, and
• the circuitry adds an absolute value of a difference between the two detection signals among the first to M-th detection signals to calculate the sum value.