# An Initial Dot Encoding Scheme with Significantly Improved Robustness and Numbers
## 3 Verification Experiments of Coded Mark Points  
In order to verify the stability and advantage of the designed coded mark points, the three aspects included illumination conditions, shooting angle and the size of marker points was analyzed, and some conclusions are summarized by this experiment. Here, the same preprocessing and edge detection are performed in this paper with schneider's coding scheme to prevent the detection results from being affected by different algorithms. In this experiment, As shown in Figure 3, 12-bit coded marks of the proposed scheme are compared with the Schneider scheme to verify the advantages and disadvantages of the scheme compared with the Schneider scheme.The camera (IO industries 2M360-CL) used f = 25 mm lenses in the experiment, and the resolution of the camera has reached 2088 \(\times\) 1024 pixel. Firstly, taking into account the impact of illumination on the mark point, the experimental method and the decoding result of the Schneider scheme are taken under the average gray value of 70-220. As shown above in Figure 4, under the influence of different illumination, especially under the condition of over saturation or under saturation illumination, the two coded schemes all show good stability. Figure 3: The verification experiments of coded mark points. Figure 2: 12-bit mark point decoding order. Secondly, under the same illumination conditions, by adjusting the shooting angle, comparing the stability of the scheme and the Schneider coded scheme, we can verify the advantages and disadvantages of the experimental scheme. As shown in Figure 5, from the above decoding results we can see that the coded marks designed in this paper can be decoded very well under the shooting angle of 0-75 degrees, however, the decoding stability of Schneider scheme becomes worse when the shooting angle is greater than 45 degree angle. Therefore, the coded scheme designed in this paper is more robust than the Schneider coded scheme in the case of a large shooting angle. Thirdly, The size of the marking points of the two schemes is discussed under the condition that both the illumination condition and the shooting angle are the same. In the experiment, the size of the mark point are 10, 15 and 20 mm, and the experiment is carried out on the condition that the average  
Figure 4: A comparative experiment on light. Figure 5: Comparing the influence of shooting angle on the stability. gray value is 160. As the resolution of the picture is 1280 \(\times\) 1024, the percentage of the pixels are 0.21%, 0.34% and 0.55% when the mark points are 10, 15 and 20 mm. As shown in Figure 6, in the case of size 10 mm, the coded scheme of this paper is not effectively detected; in the case of 15 and 20 mm, the two schemes can be decoded. By analyzing the experimental procedures, the reason for this problem is that the starting point is too small to detect. Therefore, the Schneider coded scheme has some advantages over the size of coded mark points. Lastly, by comparing the decoding stability of the coded scheme of this paper and the Schneider encoding scheme, we can obtain the results shown in the following table. Here, the standard of evaluation is the bit error rate. Through Table 2, it shows that the angle of the shooting affect the recognition of the coded mark points and the size of the coded mark point also affects the stability of the detection. The larger the size of the coded mark point, the more easily it is to recognize the coded mark point; the larger the angle of the shot, the worse the stability of the coded mark recognition. When the size of the coded mark point is 15 and 20 mm, the recognition rate of this coded scheme is generally higher than that of the Schneider coded scheme. In particular, when the size of the coded mark point is 20 mm, the recognition rate of the coded mark point below 75 degrees can reach one hundred percent. However, the coded mark of this paper is very poor when the size is 10 mm.