Gao Hongxia

A Heuristic Optimization Algorithm for Multi-head Mounter

This paper analyzes optimization algorithms of assembly time for a multi-head mounter. A step-by-step heuristic optimization algorithm is proposed to minimize the PCB assembly time for a multi-head mounter. By relaxing the restrictions on the problem and employing a flexible approach for feeder and head assignment, the algorithm reduces the assembly time by minimizing cycles of pick and placement, constructing the simultaneous pickup and implementing the nearest placement. The production results show that the proposed algorithm has good performance in practice.

A novel method for locating surface mounted components based on elliptical Fourier descriptor

This paper presents an elliptical Fourier descriptor for locating surface mounted components (SMC) in real-time environments. The proposed technique just uses the contour of SMC to estimate the rotational angle and the centroid, which is different from the traditional methods. The first-order harmonic of Elliptical Fourier descriptor is used to estimate the angle of components and the zero-order harmonic is used to estimate the centroid of components. Results of the experiments confirm that the proposed method is a powerful tool for locating SMC.

An approach for locating surface mounted devices based on phase correlation

This paper presents a model-based method for localization and measurement of various surface mounted devices. The proposed method uses all the image information and without feature extraction, it can be very accurate, efficient and robust. In our algorithm, the phase correlation is used for scale, rotation and translation estimation. In the part of scale and rotation estimation, we implement log-polar transform of magnitude spectrum; the scale and rotation are extracted by using phase correlation in log-polar space. In the part of translation estimation, we firstly generate the ideal model of surface mounted devices and adopt scale and rotation transforms to the model, and then the translation estimation can be obtained by phase correlation. Finally, representative experimental results on ideal and real gray-level surface mounted devices images show that the proposed approach is applicable to Scale-roto-translation estimation within a specified degree of accuracy. The proposed method can become an effective technique to inspect all kinds of surface mounted devices with arbitrary shapes which is suitable for a pick-and-place system used by semiconductor assembly.