Game machine

A game machine comprising:

• a game machine main body;
• a motion sensor configured to detect a predetermined motion of an object to be detected positioned within a predetermined range along a front surface of the game machine main body;
• a controller configured to determine presentation content depending on a detection timing of the predetermined motion of the object to be detected;
• and
• a display section configured to display an image according to the presentation content,
• the motion sensor including:
• a first illumination light source configured to illuminate the object to be detected located within the predetermined range;
• a second illumination light source disposed at a different position from the first illumination light source and configured to illuminate the object to be detected located within the predetermined range;
• a light source controller configured to alternately turn on the first and second illumination light sources with a predetermined period;
• a photographing section configured to photograph the object to be detected within the predetermined range while the first illumination light source is turned on to generate a first image in which the object to be detected is present and configured to photograph the object to be detected within the predetermined range while the second illumination light source is turned on to generate a second image in which the object to be detected is present;
• a storage section configured to store therein a first reference image generated by photographing the predetermined range under conditions where the first illumination light source is turned on and where the object to be detected does not exist in the predetermined range and a second reference image generated by photographing the predetermined range under conditions where the second illumination light source is turned on and where the object to be detected does not exist in the predetermined range;
• a difference image generation section configured to generate a first difference image based on a difference between the first image and the first reference image and a second difference image based on a difference between the second image and the second reference image;
• a synthesis section configured to synthesize the first and second difference images to generate a synthetic image;
• and
• a motion detection section configured to detect a position of the object to be detected on the successively generated synthesis images and to determine based on transition of the position of the object to be detected, whether the object to be detected performs the predetermined motion.