Aiming at the shortcomings such as low precision

dead zone exist in traditional contact angle encoders in overhead crane

and the marks used in visual detection systems are sensitive to rotation and tilt

a vision target detection algorithm is proposed to obtain the spatial position of the load in real time. Add a spherical marker to the load

the swing angle and rope length information by obtaining the information of the spherical marker. Firstly

the spherical center and the radius are identified by improved circle detection algorithm in the designed image processing area. Then

the space coordinates of spherical target are confirmed by the space geometry method. The experimental results indicate that the visual detection technology can provide more accurate data for control system of the overhead crane.