A signal transmitting apparatus is provided that includes a light emitter and a circuit that controls the light emitter change in luminance in frequency to transmit a signal to a receiving apparatus. The receiving apparatus includes a processor and a recording medium having a program, the program causing the processor to execute operations. The operations include obtaining first image data with a first exposure time; setting a second exposure time of the image sensor so that, in an image obtained by capturing a subject by the image sensor, a plurality of bright lines corresponding to the plurality of exposure lines included in the image sensor appear according to a change in luminance of the subject; obtaining a bright line image including the plurality of bright lines; and obtaining information by demodulating data specified by a pattern of the plurality of bright lines.