Analysis of true and false sticker breakouts’ characteristics based on mould thermal image

All 198 samples were obtained for past three years, including true and false sticker breakouts. Based on the mould thermal image of temperature rate, temperature, geometric and shape characteristics were calculated, such as maximum temperature rate, height, width, area, perimeter, circularity, rectangularity and aspect ratio. The difference of true and false sticker breakouts was compared and analysed. The results show that the maximum temperature rate of hot region is 7.13 °C/s for true sticker breakout while it is 5.27 °C/s for false sticker breakout. The minimum temperature rate of cold region is −4.31 °C/s for true sticker breakout while it is −3.43 °C/s for false sticker breakout. The maximum and minimum temperature rates of true sticker breakout are usually more than those of false sticker breakout. When the area of hot region exceeds 24,998 pixels, no sticker breakout has occurred, but there were 10 samples of false sticker breakout. The height, width and areas of hot and cold regions are more concentrated for true sticker breakouts, while false sticker breakout are more scattered. The circularity value of hot region is in the range of 0.17–0.52 for true sticker breakout, which is generally lower than the false sticker breakout (0.13–0.87). The shape of cold region is closer to a circular shape for true sticker breakout.