A display apparatus, comprising a display unit; and an image processing unit (3, 3'), wherein the display unit is configured to project light for a display image; and the image processing unit (3, 3') is configured to change polarization direction of the light for the display image and to selectively scatter or transmit the light for the display image based on the polarization direction of the light for the display image, characterised in that the display apparatus further comprising a mode selection unit, wherein the mode selection unit is configured to select a display mode, the display mode including a first distance display mode, a second distance display mode, and a dual-distance display mode; and wherein in the first distance display mode, the display unit projects light for a first display image; the image processing unit (3, 3') converts polarization direction of the light for the first display image into the first polarization direction and scatters the light for the first display image to display the first display image at a first distance; in the second distance display mode, the display unit projects light for a second display image; the image processing unit (3, 3') converts the polarization direction of the light for the second display image into the second polarization direction and transmits the light for the second display image to display the second display image at a second distance; and in the dual-distance display mode, the display unit projects light for the first display image and light for the second display image alternatively, and the image processing unit (3, 3') displays the first display image and the second display image at the first distance and the second distance, respectively. a display unit; and an image processing unit (3, 3'), wherein the display unit is configured to project light for a display image; and the image processing unit (3, 3') is configured to change polarization direction of the light for the display image and to selectively scatter or transmit the light for the display image based on the polarization direction of the light for the display image, characterised in that the display apparatus further comprising a mode selection unit, wherein the mode selection unit is configured to select a display mode, the display mode including a first distance display mode, a second distance display mode, and a dual-distance display mode; and wherein in the first distance display mode, the display unit projects light for a first display image; the image processing unit (3, 3') converts polarization direction of the light for the first display image into the first polarization direction and scatters the light for the first display image to display the first display image at a first distance; in the second distance display mode, the display unit projects light for a second display image; the image processing unit (3, 3') converts the polarization direction of the light for the second display image into the second polarization direction and transmits the light for the second display image to display the second display image at a second distance; and in the dual-distance display mode, the display unit projects light for the first display image and light for the second display image alternatively, and the image processing unit (3, 3') displays the first display image and the second display image at the first distance and the second distance, respectively.