###### Abstract
Through the improvement of the image contour extraction algorithm and the error compensation for the mechanical system, the measurement accuracy, reliability and stability were improved. This backlight image measurement method had higher requirements for the measurement environment and a larger workload [19; 20; 21]. The method of follow-up measurement for non-symmetrical axis parts was designed. The hardware system of the automatic integrated measuring machine was studied, and the position relation model between the workpiece and measuring coordinate system was established. The comprehensive measurement software for shaft parts was also developed [22]. In view of the problem that the measurement accuracy decreases due to the width of the Abbe probe, the measurement method of a crankshaft was studied, and a crankshaft servo control method based on a four-axis motion system was proposed [23]. A comprehensive parameter measuring instrument for engine crankshafts was designed. The composition scheme, measurement principle and operation process of the measurement system were introduced. The least-squares method was adopted to process the data to reduce the measurement error [24]. The roundness and cylindricity of journals are important parameters of the crankshaft, which will directly affect the life and performance of the crankshaft. Because of the characteristics of the journal form and position error, scholars pay more attention to the study of the roundness error and use it as the basis of the evaluation of the cylindricity error. Many scholars in China and abroad have studied the evaluation methods of roundness error of components. [PERSON] [25] studied the relationship between the reference worm and the circle and established the error calculation model of the minimum zone circle, the maximum inscribed circle and the minimum circumscribed circle. The results showed that it is convenient for computer processing to use reference worms instead of reference circles,the precision was high enough under actual measurement conditions. [PERSON] [26] evaluated the roundness error and its uncertainty of a workpiece by comparing the probability and statistics method with the classical LSM based on the global positioning system (GPS) standard. [PERSON] [27] proposed a hybrid method based on LSM and a new probabilistic global search Lausanne technique, which can accurately evaluate the roundness error of a workpiece. [PERSON] [28] proposed an improved artificial bee colony algorithm to evaluate the roundness error. The roundness error evaluation example also proved that the algorithm had strong accuracy and stability in evaluating the roundness error. [PERSON] [29] improved the particle swarm optimization algorithm to evaluate the roundness error. The algorithm conformed to the principle of the minimum zone method and had the advantages of strong global search ability, good stability and fast convergence speed. It was verified by an example that the accuracy of the algorithm for evaluating the roundness error is better. [PERSON] [30] proposed a novel PSO algorithm to evaluate the minimum zone roundness error by changing the inertia weight value and attaining its optimal value. The linear variable inertia weight PSO results were compared with the PSO with three different inertia weight values. Compared with GA and LSM, PSO based on inertia weight had advantages in evaluating accurate roundness error. [PERSON] [31] proposed a new teaching-learning-based optimization (TLBO) algorithm with fewer parameters for roundness error measurement, and the results were compared with the classical PSO algorithm. By comparing the accuracy and convergence time of the two advanced optimization algorithms, it was found that the two algorithms have obtained similar results, while TLBO takes a higher calculation time in comparison to PSO. [PERSON] [32] applied the constriction factor PSO (CFPSO) algorithm for evaluating different form errors, including minimum zone roundness.