## 7 Experimental Results and Discussion  
We have tested our setup in several scenarios, involving strong jamming, direct sunlight and mutual interference. For 16-bit long modulation sequence and sensor's frame rate of 480 fps we have achieved a stable live view of reflected patterns at 30 fps. The snapshots in the following figures were taken in plain and demodulated live view modes. The scene was illuminated using modulable 650 nm LED laser combined with a DOE (diffractive optical element) projecting a pattern of parallel horizontal lines.  
As it can be seen from the captured snapshots in Figures 5-11, our experimental ATRIS system demonstrates good results in closed environment and proves the feasibility of the suggested approach to compensation of the environmental factors outdoors. Even if laser projection is completely non-noticeable by the naked eye and much weaker than the interfering projection or environmental illumination, the modulation sequence can raise the level of signal pixels in the acquired distortion  
\begin{table}
\begin{tabular}{c|c c c c} \hline
**Desired sequence length (\(N\))** & 4 & 8 & 16 & 32 \\ \hline
**Number of codes in a set (\(k\))** & 2 & 3 & 4 & 5 \\ \hline
**Possible code sets (row indexes)** & 2, r\({}_{2}\) \(\in\) [3,4] & 2, r\({}_{2}\), r\({}_{3}\), r\({}_{4}\)\(\in\) & 2, r\({}_{2}\), r\({}_{3}\), r\({}_{4}\), r\({}_{5}\)\(\in\) \\  & & [5,..., 8] & [9,..., 16] & [17,..., 32] \\ \hline \end{tabular}
\end{table}
Table 1: Cyclic Orthogonal Codes selection table.  
Figure 4: Mutual interference suppression: interference pixels intensity through the frame cycle for a pair of (**a**) phase-shifted non-cyclic orthogonal codes and (**b**) cyclic orthogonal codes.  
Figure 8: Interference suppression: interference of two identical devices having non-cyclic orthogonal modulation codes. (**a**) Plane image; (**b**) demodulated image.  
Figure 10: Background noise suppression: medium sunlight suppression outdoors. (**a**,**c**) Plane image, (**b**,**d**) demodulated image.  
Figure 9: Interference suppression: interference of two identical devices with cyclic orthogonal modulation codes. (**a**) Plane image; (**b**) demodulated image.  
At the present state the described system setup has the following limitations caused by the sensor's characteristics, the setup design and its implementation:  
Figure 11: Background noised suppression: strong sunlight suppression outdoors. (**a**,**c**) Plane image, (**b**,**d**) demodulated image.  
Figure 10: _Cont._  
1. The system's maximal frame rate is limited by the maximal sensor frame rate divided by \(N\). Thus, when a longer modulation sequence is required, the frame rate degrades. This limitation can be eliminated by implementing a gated CMOS sensor capable of performing \"in-pixel\" demodulation.
2. The laser is triggered directly by the electronic shutter of the sensor and the duration of emission is limited by the sensor's exposure time. The low dynamic range of the sensor demands a reduction of the exposure time when capturing highly illuminated scenes. Since the laser power remains the same, the emitted laser energy is reduced proportionally to the reduced exposure time, so at durations of 0.01-0.02 ms the captured laser intensity level \(l\) becomes comparable to \(\delta\), which yields in increased background noise according to Equation (6). This limitation is especially noticeable with strong sunlight and reflecting surfaces, as shown in Figure 11(d).
3. The number of cyclic orthogonal codes of length \(N=2^{k}\) is limited by \(k\). Overrunning this limit leads to the \"frame collisions\" effect demonstrated in Figure 8(b).  
Since the discussed parameters are tightly correlated and directly affect the system's performance, future work will be aimed at finding an appropriate technique for adjusting them to dynamically changing scene conditions.