# Image Quality Assessment of Digital Image Capturing Devices for Melanoma Detection
## 3 Results
### Results of Sharpness and Resolution Measurements
#### 3.1.1 Cameras' Sharpness Results for the Imates(r) eSFR Test Chart  
Photos to measure the sharpness of all seven cameras were taken twice at different temperatures of the LED lights that were used for illumination, namely 3200 K and 5500 K. The sharpness measurements 10-90%, MTF50, and over/under sharpness in Table 2 below come from two areas (the rectangle just above the higher left of the chart--ROI5 and the rectangle in the centre of the chart--ROI29) of the ISO 12233 image, illustrated by red rectangles in the image presented in Figure 1. We made three shots when using the Canon EOS 800D camera. On the third shot, we used the Canon Speedlite 430 EX II flash for lighting. The results are summarised in Table 2.  
The graphs for analysing the sharpness of all captured images of the eSFR test chart with the iPhone 7 camera are presented in Figure 5. On the left are plots of the edge profile curves, and on the right side are corresponding MTF plots. The difference in sharpness parameters of the object in the left higher corner (ROI5), and the object in the image centre (ROI29) can be read from the plots. In the case of this camera, illumination with different lights had a negligible impact on the sharpness of the captured images. From the test results, we can estimate that the iPhone 7 camera software used to generate the JPG format does not force image sharpening processes. This is not the case with the other cameras we tested, especially the Samsung S10 and Huawei P10, where we measured a significant degree of over-sharpness, as shown in Table 1. All cameras tested showed better sharpness in the centre than at the edges of the images.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Camera**} & \multirow{2}{*}{\begin{tabular}{c} **Nyquist f** \\ **(LW/PH)** \\ \end{tabular} } & \multirow{2}{*}{**CT [K]**} & \multicolumn{3}{c}{**ROI 5**} & \multicolumn{3}{c}{**ROI 29**} \\ \cline{3-8}  & & & **10-90\%** & **MTF50** & **O/U Sharp** & **10-90\%** & **MTF50** & **O/U Sharp** \\  & & & **(px)** & **(LW/PH)** & **(\%)** & **(px)** & **(LW/PH)** & **(\%)** \\ \hline \multirow{2}{*}{Iphone 5s} & \multirow{2}{*}{2448} & 3200 & 1.2 & 1862 & 3.7 & 0.8 & 2322 & 14.2 \\  & & 5500 & 1.2 & 1946 & \(-\)3.3 & 0.9 & 2362 & 16.4 \\ \hline \multirow{2}{*}{Iphone 7} & \multirow{2}{*}{3024} & 3200 & 2.5 & 1260 & -25.9 & 1.3 & 2139 & 0.8 \\  & & 5500 & 2.4 & 1367 & \(-\)21.1 & 1.3 & 2305 & 7.0 \\ \hline \multirow{2}{*}{Iphone XR} & \multirow{2}{*}{3024} & 3200 & 1.1 & 2090 & 6.3 & 0.9 & 2331 & 13.6 \\  & & 5500 & 1.2 & 1927 & 20.1 & 0.9 & 2654 & 36.9 \\ \hline \multirow{2}{*}{Samsung S10} & \multirow{2}{*}{3024} & 3200 & 0.9 & 2512 & 61.4 & 0.6 & 2982 & 67.3 \\  & & 5500 & 0.7 & 2693 & 87.5 & 0.5 & 3052 & 111.9 \\ \hline \multirow{2}{*}{Huawei P10} & \multirow{2}{*}{2976} & 3200 & 1.2 & 1998 & 27.1 & 1 & 2058 & 36.8 \\  & & 5500 & 1.2 & 1932 & 19.4 & 1 & 2116 & 38.4 \\ \hline \multirow{2}{*}{Canon EOS} & \multirow{2}{*}{3458} & 3200 & 3 & 1383 & \(-\)28.1 & 1.1 & 2437 & 40.2 \\  & & 5500 & 3 & 1388 & \(-\)27.2 & 1.1 & 2440 & 45.4 \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Canon EOS \\ 800D \\ (FotoFinder) \\ \end{tabular} } & \multirow{2}{*}{4000} & 3200 & 1.9 & 1907 & 3.8 & 1.2 & 2543 & 32.8 \\  & & 5500 & 1.9 & 1856 & 5.8 & 1.2 & 2474 & 38.0 \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Canon EOS \\ 800D \\ (FotoFinder) \\ \end{tabular} } & \multirow{2}{*}{4000} & \multirow{2}{*}{5500} & \multirow{2}{*}{1.9} & \multirow{2}{*}{1856} & \multirow{2}{*}{5.8} & \multirow{2}{*}{1.2} & \multirow{2}{*}{2474} & \multirow{2}{*}{38.0} \\  & & & 1.7 & 2101 & 10.6 & 1.3 & 2415 & 27.0 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Cameras’sharpness results for the Imatest® eSFR test chart.  
Figure 5: Edge profile curves and plots with the corresponding MTF for the higher left corner of the image (ROI5) and for the centre of the image (ROI29). Images were captured with the iPhone7 camera under different illuminations with calibrated LED lights (3200 K and 5500 K).