Fast dimensional measurement method and experiment of the forgings under high temperature

Non-contact dimensional measurement of hot forgings is desirable for process control and product quality. The stereo vision method has the potential to detect the dimensions of hot forgings. However, it is necessary for the stereo vision method to obtain clear image, and to extract and match rapidly feature points of hot forgings. The spectrum selective method proposed has improved the image quality of hot parts. In this paper, based on the spectrum selective method, a fast method with the projected light stripes is presented for dimensional measurement of hot forgings. Firstly, the light stripes on the hot forging are resolved from the image by the proposed modified Gaussian model. Then, a fast sub-pixel extraction algorithm of center points of the light stripes is designed, especially for the situation of small gray variation in the image of hot forgings. Finally, the endpoints of the light stripes are employed to rapidly calculate the dimensions of hot forgings. Experiments on measuring the dimensions of hot forgings in the workshop are conducted to testify the proposed method. The experimental results indicate that the measurement method is efficient. Besides, an additional experiment in the laboratory verifies the accuracy of the presented method.