## 3 Image Feature-Based Extraction of Damage Indicators
### Through-Lane Inspection
Set a larger value of \(Lv\), according to the read matrix of the consistency line of the left element \(\xi\), obtain the position matrix of the crater \(P_{i}=[(x_{K},y_{K}),\ldots,(x_{N},y_{N})]\) and the diameter matrix \(d_{i}=[d_{K},\ldots,d_{N}]\), calculate the smallest external rectangle that contains the crater, the formation of the rectangle index \(id\), \(id\) value for the natural number from 1, the position matrix \(P_{ma}=[x_{i},y_{i}]\), and the length and width matrix of the rectangle \(S_{ma}=[w_{i},h_{i}]\). Then, calculate the minimum outer circle of the rectangle to obtain the location of the new \"crater\" and the \"diameter\" \(d_{I}\); the \"diameter\" is calculated as follows: \[d_{I}=Lv+id\] (8) Combine all rectangular length-width matrices \(S_{ma}\) into a new matrix \(S\) in the order: \[S=\left[ \begin{array}{cc}w_{1}&h_{1}\\ w_{2}&h_{2}\\ \ldots&\ldots\end{array} \right],\] (9) Delete the read data from the original crater position and diameter matrix and add the new crater position and diameter data to form a new crater position matrix \(P^{\prime}=[(x^{\prime}_{1},y^{\prime}_{1}),(x^{\prime}_{2},y^{\prime}_{2}),...,(x^{\prime}_{m},y^{\prime}_{m})]\) and diameter matrix \(d^{\prime}=[d^{\prime}_{1},d^{\prime}_{2},...,d^{\prime}_{m}]\). 5. Render the bridge deck as a whole in white, and sequentially read the new crater position matrix \(P^{\prime}\) and diameter matrix \(d^{\prime}\). If \(d^{\prime}_{i}>id-1\), it means that the crater is a rectangle; retrieve the length and width of the rectangle based on \(d^{\prime}_{i}-Lv\) and render the rectangular region in black by combining positional information. If \(d^{\prime}_{i}<id-1\), it means that the crater is a circle; render the smallest outer rectangle of the circle in black based on positional and direct information. 6. Read the new crater position matrix \(P^{\prime}\) and the diameter matrix \(d^{\prime}\). If \(d^{\prime}_{i}>id-1\), set the width of the retrieval bar to be \(\min_{i},h_{i}\) and the length of the retrieval bar to be the width of the bridge deck and the retrieval bar to be rendered in white. Start from the bottom of the area, perform the \"and\" operation of the retrieval bar with the bridge deck, delete the white areas whose widths are smaller than the width of the retrieval bar, and calculate the sum of downward integer values of the length of the white areas divided by the width of the vehicle after the operation. Calculate the length of each white area after the operation divided by the width of the vehicle \(W^{\prime}\) and the downward integer value of \(OP\). After retrieving this area, record the information of this crater and the minimum value of its \(OP\); if \(d^{\prime}_{i}<id-1\), set the width of the retrieval bar to \(d_{i}^{\prime}/2\), and the rest of the operation is the same as above. Finally, compare the \(OP\) values and output the minimum value and its crater information. 7. Based on the crater information and \(OP\) values from the previous step, calculate whether the crater has any craters in the range \(W^{\prime}OP\). If the crater exists, then \(OP=OP-1\); if not, then \(OP=OP\). The final calculated \(OP\) value is the number of lanes. The algorithm is illustrated graphically in Figure 6.  
The pass-through lane detection algorithm can quickly output the number of pass-through lanes on the bridge deck after the strike through the image, and the algorithm has a low complexity which calculates the number of pass-through lanes based on the relationship between the crater information, the effective distance between the craters, and the width of the vehicle, which ensures the validity of the output results.