Summary: By watching the reflection in the glass window, one can often observe a two-layered image consisting of a front-surface reflection from a glass and a rear-surface reflection through the glass. The transparent glass plate reflects and transmits the incident light from its front surface. The transmitted light is then reflected from the rear surface and is transmitted again to the air through the front surface. These two light paths create a layered image comprising two identical images with a specific displacement depending on the object range. Estimating the object range requires the accurate detection of the image shift in the layered image. This paper presents a study of the shift estimation method using Fourier transformation of the layered image. The maximum location in the Fourier transform of the Fourier power spectrum of the layered image indicates the image shift. Experimental results demonstrate the effectiveness of the method compared with a method using an autocorrelation function.