A Mixed-Reality, MR, device, for augmenting human vision in limited-visibility environments, the MR device comprising: a visible-range sensor for capturing a visible-range representation of a real-world scene surrounding the MR device with a range commensurate with human vision, an extended-range sensor for capturing an extended-range representation of the real-world scene with an extended range wider than the range commensurate with human vision, a display, and processing circuitry causing the MR device to be operative to: generate a visible-range representation of edges of one or more physical objects present in the real-world scene by extracting edges from the visible-range representation captured by the visible-range sensor, and generate an extended-range representation of edges of the one or more physical objects by extracting edges from the extended-range representation captured by the extended-range sensor, characterized by the processing circuitry further causing the MR device to be operative to: generate a delta representation of edges of the one or more physical objects, comprising edges present in the extended-range representation of edges but absent in the visible-range representation of edges, and display the delta representation of edges on the display. a visible-range sensor for capturing a visible-range representation of a real-world scene surrounding the MR device with a range commensurate with human vision, an extended-range sensor for capturing an extended-range representation of the real-world scene with an extended range wider than the range commensurate with human vision, a display, and processing circuitry causing the MR device to be operative to: generate a visible-range representation of edges of one or more physical objects present in the real-world scene by extracting edges from the visible-range representation captured by the visible-range sensor, and generate an extended-range representation of edges of the one or more physical objects by extracting edges from the extended-range representation captured by the extended-range sensor, characterized by the processing circuitry further causing the MR device to be operative to: generate a delta representation of edges of the one or more physical objects, comprising edges present in the extended-range representation of edges but absent in the visible-range representation of edges, and display the delta representation of edges on the display. generate a visible-range representation of edges of one or more physical objects present in the real-world scene by extracting edges from the visible-range representation captured by the visible-range sensor, and generate an extended-range representation of edges of the one or more physical objects by extracting edges from the extended-range representation captured by the extended-range sensor, characterized by the processing circuitry further causing the MR device to be operative to: generate a delta representation of edges of the one or more physical objects, comprising edges present in the extended-range representation of edges but absent in the visible-range representation of edges, and display the delta representation of edges on the display. generate a delta representation of edges of the one or more physical objects, comprising edges present in the extended-range representation of edges but absent in the visible-range representation of edges, and display the delta representation of edges on the display.