Fluidized bed is an important unit operation used in many industries for different applications, including drying, coating and granulation. When hot inlet air is used, the particles and the fluidized bed wall are heated in the same time. In order to understand the heating process of the particles, it is necessary to online monitor the particle temperature.

Due to the influence of the air around the particles, contact devices (e.g. thermocouple probes) are not suitable for measuring the fluidizing particles. Therefore, thermal cameras were used recently to online monitor the temperature of the fluidizing particles non-invasively. In the literature, the particles in the thermal images were generally distinguished from the fluidized bed wall. However, due to the particle movement and the focus of the thermal camera, when using a thermal camera to monitor the particles in a cylindrical 3D fluidized bed, there will be clear particles and blurred particles in the thermal images. The blurred particles can affect the accuracy of the particle temperature measurement.

In this paper, based on the size and shape of the particles, the clear particles in the thermal images were identified by filtering the fluidized bed wall and the blurred particles. Then the temperature measured from these identified particles were experimentally calibrated. Using this technique, the online temperature of the particles was successfully measured together with the online temperatures of the air and the fluidized bed wall.

流化床是许多行业中用于不同应用（包括干燥，包衣和制粒）的重要单元操作。当使用热进气时，颗粒和流化床壁同时加热。为了了解颗粒的加热过程，有必要在线监测颗粒温度。

由于颗粒周围空气的影响，接触装置（例如热电偶探头）不适用于测量流化颗粒。因此，近来使用热像仪来非侵入性地在线监测流化颗粒的温度。在文献中，热图像中的颗粒通常与流化床壁区分开。但是，由于粒子运动和热像仪的焦点，当使用热像仪监视圆柱形3D流化床中的粒子时，热图像中会出现清晰的粒子和模糊的粒子。模糊的颗粒会影响颗粒温度测量的准确性。

在本文中，根据颗粒的大小和形状，通过过滤流化床壁和模糊的颗粒来识别热图像中的透明颗粒。然后，对从这些鉴定出的颗粒测得的温度进行实验校准。使用该技术，可以成功地测量颗粒的在线温度以及空气和流化床壁的在线温度。