Distance measuring system and distance measuring method

A distance measuring method carried out using a distance measuring system,

• the distance measuring system including:
• an irradiation unit for emitting a pulsed light to a target object, wherein the pulsed light is reflected by the target object;
• a solid-state image sensing device for generating photoelectrons depending on the energy of the reflected light received in a light-receiving period predetermined for the emission timing of the pulsed light, and cumulatively storing therein the generated photoelectrons;
• and
• an arithmetic processing unit for determining a distance to the target object according to a time-of-flight process using information concerning the photoelectrons cumulatively stored in the solid-state image sensing device,
• wherein:
• the light-receiving period includes a first light-receiving period and a second light-receiving period;
• and
• the first light-receiving period is a part of a rise period during which the intensity of the reflected light received by the solid-state image sensing device rises, and the second light-receiving period includes a peak point of the intensity of the reflected light received by the solid-state image sensing device and a fall period during which the intensity thereof falls,
• the method comprising:
• with the solid-state image sensing device, cumulatively storing therein photoelectrons generated depending on the energy of the light received in the first light-receiving period, and also cumulatively storing therein photoelectrons generated depending on the energy of the light received in the second light-receiving period;
• and
• with the arithmetic processing unit, determining the distance to the target object using a light energy ratio obtained by dividing information concerning the photoelectrons cumulatively stored in the second light-receiving period by information concerning the photoelectrons cumulatively stored in the first light-receiving period.