# Resolution Aspects for Near-Field Projections
## 4 Discussion  
This work's analysis considers the dependencies of the observer's viewing distance, different ambient lighting scenarios and various projection content. All discussed resolution levels are the 90% values of the logistic regression function. This quality threshold level is selected to guarantee a high-quality resolution requirement and consider the worst-case scenario, since the executed studies had a fine-grained asphalt surface. However, previous studies examined resolution requirements for displays or projection screens in cinemas, which have a projection surface with nearly ideal characteristics without a tilted view. However, none derives the necessary characteristics from the customer- or pedestrian-orientated perspective, i.e., the perspective of the receivers of near-field projections in future mobility.  
The results of symbol- and text-based projections in PGS and DDS are lower than the resolution of the gap size between the two lines of 85.73 px/\({}^{\circ}\) for PGS and 52.93 px/\({}^{\circ}\) for DDS in the pre-study. In conclusion, the difference between the results in Table 2 and the pre-study, which defines the maximum perceived resolution on the projection surface, ensures that the tested quality levels were resolvable at the closest observation distance of 1 m. Furthermore, this guarantees that the resulting resolution of symbol- and text-based projections regarding the evaluation aspect of quality has other requirements than the resolvable detail, which is less complex and relates to the static visual acuity task [36].  
Therefore, the analyses conducted in this work define some dependencies and simplifications for perceived resolution requirements. First, the impact of ambient lighting is significant (Table 1) for all combinations and defines an explicit dependency in the participants' perception. This significant difference is due to the interaction of rods and cones in the mesopic range of adaptation luminance, which is linked to the increasing acuity at increasing luminance levels [38]. Hence, this phenomenon confirms the use case  
Figure 5: Results of the analyzed data by using the logistic regressing Equations (3) and (4) for extracting the 90% threshold for the resolution in px/\({}^{\circ}\) with the corresponding probability of satisfaction in the DDS. (**a**) Detailed illustration of the logistic regression of the symbol-based projection in the DDS, including the raw data, which is marked with “X” for 1 m data, with circles for 3 m data and triangles for 5 m data; (**b**) Detailed logistic regression of the text-based projection in the DDS including the raw data which is marked with X for 1 m data, with circles for 3 m data and triangles for 5 m data.  
of near-field projections for text- and symbol-based projection content in DDS (-6 cd/m2) or PGS (-1 cd/m2) due to [PERSON]'s definition [36] of maximal acuity above 2 cd/m2.  
Second, the impact of the projection content focuses on the effective resolution in Table 2 to increase the importance of the resolution values and not just to focus on significance levels [44]. Table 2 also displays the spread of the results with 95% confidence intervals, which deliver an overlay of the symbol- and text-based projection content in the PGS and DDS. The overlay leads to a tendency of a uniform projection system for both projection content varieties regarding the perceived resolution.