We present preliminary results for threshold detection of sharp-edged and "fuzzy" bars and discs superimposed on noiseless and noisy backgrounds. The luminance profiles for the "fuzzy" targets were approximately gaussian. The background quantum noise is optical density fluctuation in nominally uniformly exposed radiographs. The measurements were done using the method of adjustment. Our results for sharp-edged targets agreed with previously published work. Our "fuzzy" target results are novel and demonstrate minima in the contrast-target size curve. The minima were near S to 10 milliradians diameter for discs and 2 to 4 milli-radians width for bars. The increasing threshold slope for large targets suggests a gradient detection process.