That's an old shoe-fitting x-ray machine, which was a popular gimmick in shoe stores in the late 1940s and early 1950s. The machine went the way of the dodo bird when it was discovered that the hazards from x-ray radiation weren't worth the proper fit of shoes:
The primary component of a shoe-fitting x-ray unit was the fluoroscope which consisted essentially of an x-ray tube mounted near the floor and wholly or partially enclosed in a shielded box and a fluorescent screen. The x-rays penetrated the shoes and feet and then struck the fluorescent light. This resulted in an image of the feet within the shoes. The fluorescent image was reflected to three viewing ports at the top of the cabinet, where the customer, the salesperson, and a third person (your mother?) could view the image at the same time.
The radiation hazards associated with shoe fitting x-ray units were recognized as early as 1950. The machines were often out of adjustment and were constructed so radiation leaked into the surrounding area.