A time-of-flight sensor for capturing a three-dimensional (3D) image of an object, includes: a light source for emitting projection light pulses at the object according to a projection signal; an array of pixel circuits for sensing reflection light pulses and storing image charges according to the reflection light pulses; and a processing circuit for calculating a first sum of first portions of the image charges and a second sum of second portions of the image charges to generate a distance information signal of the 3D image of the object simultaneously, wherein in one accumulation period, the first portion of the image charges is generated during a first time period, and the second portion of the image charges is generated during a second time period, wherein the second time period is directly following the first time period in the accumulation period.