# CubeSat Imaging Payload Design for Environmental Monitoring of Greenland
## 2 Materials and Methods
### System Design  
Several camera sensor brands can provide cameras and their corresponding support. For CubeSats, it is typical to use COTS components and we focused on industrial machine vision camera ranges for their small size and rugged specifications. In terms of sensors, we chose Sony's IMX-series since they provide a high-quality CMOS image sensor. Furthermore, The IMX-series models are among the sensors most frequently used in industrial cameras. One of the reasons for the high image quality of IMX-series is the unique technology from Sony called Exmor, in which the noise-reduced analog signal recorded by the sensor is converted into a digital signal directly when the pixels are read out [[https://www.sony-semicon.com/en/products/is/camera/index.html](https://www.sony-semicon.com/en/products/is/camera/index.html)]([https://www.sony-semicon.com/en/products/is/camera/index.html](https://www.sony-semicon.com/en/products/is/camera/index.html)) (accessed on 9 December 2024), (Sony, Copenhagen, Denmark). The IMX series sensor provides different options regarding the target application; in this case, the IMX-541 fits all requirements, and the IMX-545 only lacks the aspect ratio requirement, which is affordable in the application and is also considered. As a result, Table 3 shows how the IMX-series sensor fits the established requirements. Once the camera sensor was targeted, several camera providers used these sensors to build robust cameras; we established contact vendors to obtain the camera datasheet and its support. It should be noted that we placed high priority on non-technical issues listed under Recam 12 and included vendor support, documentation and community activity in our deliberations. It is our experience that these factors have an outsized impact on ease of development and project timelines. Table 4 shows the cameras that best \begin{table}
\begin{tabular}{c c c c} \hline ID & Requirement & Specification & Priority \\ \hline Repro\_1 & Dimensions & \(10\times 70\times 80\) mm & High \\ \hline Repro\_2 & Hardware accelerator & TPU or NPU & High \\ \hline Repro\_3 & Time to reboot & ms & High \\ \hline Repro\_4 & Multi-camera setups & 3 & High \\ \hline Repro\_5 & Operating temperature range & \(-20\geq+65\,^{\circ}\)C & High \\ \hline Repro\_6 & Documentation & ruggedness vibration and thermals & High \\ \hline Repro\_7 & Driver compatblblity & linux & High \\ \hline Repro\_8 & ML support & Frameworks & High \\ \hline Repro\_9 & Nominal Power & \(<\)3 W & High \\ \hline Repro\_10 & Peak Power & \(<\)5 W & High \\ \hline Repro\_11 & Sleep modes & \(<\)1 W & High \\ \hline \end{tabular}
\end{table} 
Table 2: IPU requirements. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Requirement**} & \multicolumn{4}{c}{**Sensors’ Camera**} \\ \cline{2-5}  & **IMX304** & **IMX253** & **IMX545** & **IMX541** \\ \hline Recam\_1 & & & ✓ & ✓ \\ \hline Recam\_2 & & \(\bullet\) & \(\bullet\) & ✓ \\ \hline Recam\_3 & ✓ & ✓ & ✓ & ✓ \\ \hline Recam\_4 & ✓ & ✓ & ✓ & ✓ \\ \hline Recam\_5 & ✓ & ✓ & ✓ & ✓ \\ \hline Recam\_6 & ✓ & ✓ & ✓ & ✓ \\ \hline Recam\_7 & & & ✓ & ✓ \\ \hline Recam\_8 & ✓ & ✓ & ✓ & ✓ \\ \hline \end{tabular}
\end{table} 
Table 3: IMX sensor evaluation. Fully covered: ✓, partially covered: \(\bullet\). matched the established requirements. In this case, Alvium cameras provide the most suitable configuration, especially the power consumption requirement. Therefore, Alvium U-1242 matches all requirements, and its friendly software environment allows a feasible integration. In the first integration round, this camera was selected. On the IPU benchmarking side, we rigorously evaluated the IPU's processing speed, accuracy, and overall computational capabilities using a comprehensive set of benchmark results developed by another team within the project [4]. The benchmarking process encompasses a range of image-processing tasks, including image recognition, feature extraction, and real-time processing.