Devices, methods, and software are disclosed for an interactive user interface for capturing a frame of image data having a representation of a feature. In an illustrative embodiment, a device includes an imaging subsystem, one or more memory components, and one or more processors. The imaging subsystem is capable of providing image data representative of light incident on said imaging subsystem. The one or more memory components include at least a first memory component operatively capable of storing an input frame of the image data. The one or more processors may be enabled for performing various steps. One step may include receiving the image data from the first memory component. Another step may include attempting to identify linear features defining a candidate quadrilateral form in the image data. Another step may include providing user-perceptible hints for guiding a user to alter positioning of the device to enhance a capability for identifying the linear features defining a candidate quadrilateral form in the image data.