Algorithm 2 Optimization algorithm

$SCS$: The sensor coordinate system

$CCS$: The container(global) coordinate system

(1) Acquire sensor data.

Capture a depth frame from D435

if the depth frame is not successfully captured then

return the error code of ’$-1$’

end if

Calculate point clouds from the depth frame

(2) Generate 2D depth map.

Transform the 3D point clouds from SCS to CCS

Project every point cloud ($x_i,y_i,z_i$) into 2D depth map by setting the value at ($\lfloor x_i\rfloor$, $\lfloor y_i\rfloor$) to $z_i$

Occupy the empty pixels of the map image by linear interpolation with the adjacent pixels

Apply $3\times 3$ sized mean filter to reduce noises

(3) Run differential evolution (DE) algorithm.

Initialize the DE algorithm

Set input bounds of $h_{thres}$ and $\mathbf{p}$

Select appropriate configuration parameters

while the termination condition is not met do

for each solution candidate do

Perform (1) and (2)

Obtain $A_f$ with respect to $h_{thres}$ using the generated depth image

Calculate the cost function

end for

Update solution candidates using DE update process

end while

Store the final solution along with its cost function value

(4) Return $h_{thres}$ and $\mathbf{p}$.

Repeat (3) three times

Return the solution ($h_{thres}$, $\mathbf{p}$) with the smallest cost function value