Vision Res.(13) Roetling et.al.
Research into Visual Perception conducted by Roetling et.al.
In common with Aulhorn before them, Roetling et.al. also investigated human visual perception using simple two-dimensional shapes. They considered human detection and recognition of images while investigating theoretical prediction of the quality of photographic images.
As part of their work they considered the problem of human observers deciding whether a given image of an object is a square or a circle. The approach described involved the analysis of images in terms of spatial frequencies, which is a technique for describing images mathematically. To predict the human recognition of two-dimensional objects generally, using the square/circle example, the spectrum of the difference of the two possible object patterns was evaluated numerically. A contour plot of this function was included, where the frequency units had been normalized so that the unit of frequency is the reciprocal of the length of the side of the square.
The importance of using a square and circle of the same area and contrast was stressed, and it was stated that if the objects had not been chosen according to these conditions then the decision would be most heavily weighted near the low frequencies and would be dependent more on contrast or size, than on shape.
For more about this work see: P.G.Roetling, E.A.Trabka & R.E.Kinzly, "Theoretical Prediction of Image Quality", J.O.S.A., Vol.58, No.3, pp.342-346 (1968).
This section includes summaries of historial research and theories of human visual perception of simple two-dimensional objects. For more about the human visual system see The Eye, Parts of Eye, Eye & Vision Disorders, Ophthalmological Procedures.