An apparatus of an optical scanner (200; 1502; 1902) for scanning a subject (104; 412; 1514; 1518; 1914; 1918), the apparatus comprising: interface circuitry including an input to receive an at least one image (626; 1520; 1530; 1920; 1930) from at least one image-capture device (305; 1504; 1904) of the optical scanner (200; 1502; 1902); and controller circuitry coupled to the interface circuitry and the input, the controller circuitry operative to process the at least one image (626; 1520; 1530; 1920; 1930) to determine ranging between the optical scanner (200; 1502; 1902) and the subject (104; 412; 1514; 1518; 1914; 1918) based on (a) projection of at least two aimer beams (1510A, 1510B; 1910A, 1910B) by an aimer transmitter system (312; 212; 212A, 212B; 1508; 1908) of the optical scanner (200; 1502; 1902) to produce at least two corresponding reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) off of a surface of the subject (104; 412; 1514; 1518; 1914; 1918), and (b) detection of a position of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930), wherein: the position of at least one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930) is a primary indicator of a distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904) of the optical scanner (200; 1502; 1902); and the at least one image (626; 1520; 1530; 1920; 1930) includes a secondary indicator of the distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904), the secondary indicator corresponding to the position of a second one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930), characterized in that the secondary indicator is used in combination with the first indicator to detect an occurrence of an optical misalignment of the optical scanner (200; 1502; 1902). interface circuitry including an input to receive an at least one image (626; 1520; 1530; 1920; 1930) from at least one image-capture device (305; 1504; 1904) of the optical scanner (200; 1502; 1902); and controller circuitry coupled to the interface circuitry and the input, the controller circuitry operative to process the at least one image (626; 1520; 1530; 1920; 1930) to determine ranging between the optical scanner (200; 1502; 1902) and the subject (104; 412; 1514; 1518; 1914; 1918) based on (a) projection of at least two aimer beams (1510A, 1510B; 1910A, 1910B) by an aimer transmitter system (312; 212; 212A, 212B; 1508; 1908) of the optical scanner (200; 1502; 1902) to produce at least two corresponding reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) off of a surface of the subject (104; 412; 1514; 1518; 1914; 1918), and (b) detection of a position of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930), wherein: the position of at least one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930) is a primary indicator of a distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904) of the optical scanner (200; 1502; 1902); and the at least one image (626; 1520; 1530; 1920; 1930) includes a secondary indicator of the distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904), the secondary indicator corresponding to the position of a second one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930), characterized in that the secondary indicator is used in combination with the first indicator to detect an occurrence of an optical misalignment of the optical scanner (200; 1502; 1902). the position of at least one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930) is a primary indicator of a distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904) of the optical scanner (200; 1502; 1902); and the at least one image (626; 1520; 1530; 1920; 1930) includes a secondary indicator of the distance between the surface of the subject (104; 412; 1514; 1518; 1914; 1918) and the at least one image-capture device (305; 1504; 1904), the secondary indicator corresponding to the position of a second one of the at least two aimer-beam reflections (1512A, 1512B; 1516A, 1516B; 1912A, 1912B; 1916A, 1916B) within the at least one image (626; 1520; 1530; 1920; 1930), characterized in that the secondary indicator is used in combination with the first indicator to detect an occurrence of an optical misalignment of the optical scanner (200; 1502; 1902).