Abstract: The development status and characteristics of the vision sensor were discussed.According to the characteristics of optical path and surface thermal conduction of Cr plating layer,the common CCD camera was chosen to collect the arc reflectance from the solid surface and the thernal irradiation from the hot workpiece within the near infrared area.With the characteristics of the near infrared spectrum and the varied tendency of spectrum respondence of the CCD camera,the clear image was obtained in the band area around 980 nm.The imaging principle of the solid surface of Cr plating layer heated by plasma was analyzed,and then useful information was gotten by image processing on the basis of analyzing the image characteristic of the heated area.