Table 1. Summary quantitative image quality and illumination metrics and test targets.

Equation(#)	Metric	Formula	Test Target
1	Minimal Resolvable Feature Size (micron)	$\frac{1000}{2^{(Group\#+1+\frac{Element\#-1}{6})}}$, Each group of Ronchi rulings consists of six elements, numbered from 1 to 6 (large to small physical size). The group and element of the smallest discernable set will provide resolvable feature size.	USAF 1951 (#R3L3S1P;Thorlabs Inc., Newton NJ)
2	Diagonal Field of View (mm)	$\sqrt{\begin{array}{l}{\left[(\frac{\text{Total}\#\text{of}\text{Horizontal}\text{Detector}}{\text{Horizontal}\text{Line}\text{Length}})*(\frac{2.5\text{mm}}{2^{\left(Group\#+\frac{Element\#-1}{6}\right)}})\right]}^2\\ +{\left[(\frac{\text{Total}\#\text{of}\text{Vertical}\text{Detector}}{\text{Vertical}\text{Line}\text{Length}})*(\frac{2.5\text{mm}}{2^{\left(Group\#+\frac{Element\#-1}{6}\right)}})\right]}^2\end{array}}$, The Total # of Pixels in the Horizontal Detector axis = 2592, the Total # of Pixels in the Vertical Detector axis = 1944, the Horizontal Line Length = width in pixels of the selected vertical Ronchi ruling, the Vertical Line Length = width in pixels of the selected horizontal Ronchi ruling. The Group and Element correspond to the selected Ronchi ruling.
3	Depth of Focus (mm)	A 45° angled face resolution target with horizontal and vertical lines at a frequency of 5 line pairs per mm, corresponding to a feature size of 31.25 μm.	5-15DOF (#54–440, Edmund Optics, Barrington NJ)
4	Standard Mobile Imaging Architecture (SMIA) Television Distortion (%)	$\frac{(A-B)}{B}*100\%$ and $A=\frac{A_1-A_2}{2}$, where A1 and A2 are the outer side lengths of a square and B is the distance between the midpoints of the sides of the square A1 and A2. “+” = pincushion distortion and “-” = barrel distortion	SFRplus #CoG (imatest LLC., Boulder CO)
5a	Color Reproduction Error with Luminance Difference	$\Delta E_{ab}^{*}=\sqrt{({(\Delta L^{*})}^2+{(\Delta a^{*})}^2+{(\Delta b^{*})}^2)}$, L* for lightness (or luminosity in the z axis), and x- and y-axis are cube root transforms of color data in a* and b*, color-opponent dimensions	X-Rite Rez Checker (#87–422; Edmund Optics, Barrington NJ)
5b	Color Reproduction Error	$\Delta C_{ab}^{*}=\sqrt{({(\Delta a^{*})}^2+{(\Delta b^{*})}^2)}$, x- and y-axis are cube root transforms of color data in a* and b*, color-opponent dimensions
6	Percentage Specular Reflection	$\frac{\#\text{of}\text{saturated}\text{pixels}}{\text{total}\#\text{of}\text{pixels}}*100\%$, where a saturated pixel defined as pixel intensity ≥ 250.	#s504 Zoe (Gaumard Scientific, Miami FL)
7	Weber’s Contrast Ratio	$C_W=\frac{I_B-I_F}{I_B}$, IB = Background Pixel Intensity IF = Foreground Pixel Intensity
8	Thermal Safety	IEC 60601–1 temperature limit of <48°C after 1 hour continuous operation	N/A

Minimal threshold used for our study was C_W ≥ 0.5.