This article [Opt. Eng. 53(6), 061610 (2014)] was originally published on 16 December 2013 with incorrect mathematical symbols in two equations. Equations 12 and 13 originally appeared as below:

## (12)

$$\mathrm{cos}\text{\hspace{0.17em}}{\gamma}_{2}=\frac{\mathrm{tg}\text{\hspace{0.17em}}\alpha \text{\hspace{0.17em}}\mathrm{cos}\text{\hspace{0.17em}}\phi ({x}_{2}-{x}_{1})+\mathrm{tg}\text{\hspace{0.17em}}\alpha \text{\hspace{0.17em}}\mathrm{sin}\text{\hspace{0.17em}}\phi ({y}_{2}-{y}_{1})-({z}_{2}-{z}_{1})}{\sqrt{{({x}_{2}-{x}_{1})}^{2}+{({y}_{2}-{y}_{1})}^{2}+{({z}_{2}-{z}_{1})}^{2}}\sqrt{1+{\mathrm{tg}}^{2}\alpha}}\phantom{\rule{0ex}{0ex}}\times (0\le {\gamma}_{2}\le \frac{\pi}{2}),$$## (13)

$$\mathrm{cos}\text{\hspace{0.17em}}{\eta}_{2}=\frac{-({z}_{2}-{z}_{1})}{\sqrt{{({x}_{2}-{x}_{1})}^{2}+{({y}_{2}-{y}_{1})}^{2}+{({z}_{2}-{z}_{1})}^{2}}}\phantom{\rule{0ex}{0ex}}\times (0\le {\eta}_{2}\le \frac{\pi}{2}).$$The corrected equations are:

## (12)

$$\mathrm{cos}\text{\hspace{0.17em}}{\gamma}_{2}=\frac{\mathrm{tg}\text{\hspace{0.17em}}\alpha \text{\hspace{0.17em}}\mathrm{cos}\text{\hspace{0.17em}}\phi ({x}_{2}-{x}_{1})+\mathrm{tg}\text{\hspace{0.17em}}\alpha \text{\hspace{0.17em}}\mathrm{sin}\text{\hspace{0.17em}}\phi ({y}_{2}-{y}_{1})-({z}_{2}-{z}_{1})}{\sqrt{{({x}_{2}-{x}_{1})}^{2}+{({y}_{2}-{y}_{1})}^{2}+{({z}_{2}-{z}_{1})}^{2}}\xb7\sqrt{1+{\mathrm{tg}}^{2}\alpha}}\phantom{\rule[-0.0ex]{2em}{0.0ex}}(0\le {\gamma}_{2}\le \frac{\pi}{2}),$$## (13)

$$\mathrm{cos}\text{\hspace{0.17em}}{\eta}_{2}=\frac{-({z}_{2}-{z}_{1})}{\sqrt{{({x}_{2}-{x}_{1})}^{2}+{({y}_{2}-{y}_{1})}^{2}+{({z}_{2}-{z}_{1})}^{2}}}\phantom{\rule[-0.0ex]{2em}{0.0ex}}(0\le {\eta}_{2}\le \frac{\pi}{2}).$$The paper was corrected online on 18 December 2013.