A display apparatus (100, 200) comprising: at least one light source (102, 202); at least one camera (104, 204); head-tracking means (106, 206); and at least one processor (108, 208) configured to: - obtain a three-dimensional model of a real-world environment; - control the at least one camera to capture a given image of the real-world environment, whilst processing head-tracking data obtained from the head-tracking means to determine a pose of a user's head with respect to which the given image is captured; - determine a region of the three-dimensional model that corresponds to said pose of the user's head; - compare a plurality of features extracted from the region of the three-dimensional model with a plurality of features extracted from the given image, to detect at least one object present in the real-world environment; - employ an environment map of a mixed-reality environment to generate an intermediate mixed-reality image based on the pose of the user's head; - embed the at least one object in the intermediate mixed-reality image to generate a mixed-reality image; and - display the mixed-reality image via the at least one light source. at least one light source (102, 202); at least one camera (104, 204); head-tracking means (106, 206); and at least one processor (108, 208) configured to: - obtain a three-dimensional model of a real-world environment; - control the at least one camera to capture a given image of the real-world environment, whilst processing head-tracking data obtained from the head-tracking means to determine a pose of a user's head with respect to which the given image is captured; - determine a region of the three-dimensional model that corresponds to said pose of the user's head; - compare a plurality of features extracted from the region of the three-dimensional model with a plurality of features extracted from the given image, to detect at least one object present in the real-world environment; - employ an environment map of a mixed-reality environment to generate an intermediate mixed-reality image based on the pose of the user's head; - embed the at least one object in the intermediate mixed-reality image to generate a mixed-reality image; and - display the mixed-reality image via the at least one light source. - obtain a three-dimensional model of a real-world environment; - control the at least one camera to capture a given image of the real-world environment, whilst processing head-tracking data obtained from the head-tracking means to determine a pose of a user's head with respect to which the given image is captured; - determine a region of the three-dimensional model that corresponds to said pose of the user's head; - compare a plurality of features extracted from the region of the three-dimensional model with a plurality of features extracted from the given image, to detect at least one object present in the real-world environment; - employ an environment map of a mixed-reality environment to generate an intermediate mixed-reality image based on the pose of the user's head; - embed the at least one object in the intermediate mixed-reality image to generate a mixed-reality image; and - display the mixed-reality image via the at least one light source.