Fig. 2.

a) Percentage of analysed studies that compare assay performance with multiple phones, colour channels/spaces and percentage of analysed publications that use a light-shielding box or not. The percentage of publications that report using the phones' flashlight for illumination is given in respect to the reporting systems without light-shielding box. b) Proportion of colour spaces mentioned in the analysed publications. RGB + others indicates proportion of publications analysing RGB performance and at least one additional colour space. Lux indicates light intensity measured by the ambient light sensor of the smartphone instead of the CMOS camera. Inset proportions of the various colour channels utilised within RGB colour space. R/B means R and B channel used for different targets. Combi means various channel values were combined mathematically and related to the analytical signal. c) Proportions of various illumination sources and other optical hardware used to perform assays within a light-shielding box. d) Proportions of software used for data analysis, (i) SBDs with in-house developed software, (ii) SBDs that utilise existing colour apps, (iii) SBDs with off-phone data analysis using PC based software. NS is not specified. LED is Light-emitting diodes, EL is Electroluminescence, TL is tube light, UV is ultraviolet.