A robot cleaner comprising: a main body configured to clean a floor within a cleaning area; a light irradiation unit configured to irradiate a region of the cleaning area; an image sensor including a plurality of lines of pixels, wherein the image sensor is arranged to sequentially expose each line of pixels for an exposure time and to form images of the region of the cleaning area using signals output from the lines of pixels; an image processing unit configured to: construct a first image of the region from a plurality of first signals respectively output in sequence from the lines of pixels after respective first exposures; ignore a plurality of second signals respectively output in sequence from the lines of pixels after respective second exposures; and construct a second image of the region from a plurality of third signals respectively output in sequence from the lines of pixels after respective third exposures; and a controller configured to control the light irradiation unit to: irradiate the region during the first exposures but stop irradiation of the region between a first time before all first exposures are completed and a second time before all second exposures are completed, wherein the controller is arranged to set irradiation timing of light output by the light irradiation unit so that all of the lines of pixels are exposed for at least a minimum designated time period during irradiation of light. a main body configured to clean a floor within a cleaning area; a light irradiation unit configured to irradiate a region of the cleaning area; an image sensor including a plurality of lines of pixels, wherein the image sensor is arranged to sequentially expose each line of pixels for an exposure time and to form images of the region of the cleaning area using signals output from the lines of pixels; an image processing unit configured to: construct a first image of the region from a plurality of first signals respectively output in sequence from the lines of pixels after respective first exposures; ignore a plurality of second signals respectively output in sequence from the lines of pixels after respective second exposures; and construct a second image of the region from a plurality of third signals respectively output in sequence from the lines of pixels after respective third exposures; and construct a first image of the region from a plurality of first signals respectively output in sequence from the lines of pixels after respective first exposures; ignore a plurality of second signals respectively output in sequence from the lines of pixels after respective second exposures; and construct a second image of the region from a plurality of third signals respectively output in sequence from the lines of pixels after respective third exposures; and a controller configured to control the light irradiation unit to: irradiate the region during the first exposures but stop irradiation of the region between a first time before all first exposures are completed and a second time before all second exposures are completed, irradiate the region during the first exposures but stop irradiation of the region between a first time before all first exposures are completed and a second time before all second exposures are completed, wherein the controller is arranged to set irradiation timing of light output by the light irradiation unit so that all of the lines of pixels are exposed for at least a minimum designated time period during irradiation of light.