The graph-analytical method (gray model) for estimating the true temperature of an opaque material from both above and below at the unknown character of emissivity dependence on the wavelength is presented. It is shown that if the diagram of spectral distribution of inverse radiance temperatures in the selected spectral range can be approximately represented by a line, convex downwards, then the obtained value of the spectral ratio temperature limits the true temperature from above. If the diagram of indicated dependence in the spectral interval can be represented by a line, convex upwards, then the obtained value of the spectral ratio temperature limits the true temperature from below. The solution to this inverse problem should be combined with the solution to the direct problem. As a result, additional information on the spectral distribution of the material emissivity in the selected spectral range appears. In addition, this is verification of the assumptions made. The paper also provides an example of processing experimental data known from publications.

提出了一种图形分析方法（灰色模型），用于根据发射率对波长的未知特性从上方和下方估算不透明材料的真实温度。可以看出，如果所选光谱范围内的反向辐射温度的光谱分布图可以近似地由一条线（向下凸）表示，则所获得的光谱比温度值将从上方限制真实温度。如果可以用一条线（向上凸）表示光谱区间中指示的依存关系图，则所获得的光谱比温度值将从下方限制真实温度。反问题的解决方案应与直接问题的解决方案结合起来。结果是，将显示有关所选光谱范围内材料发射率光谱分布的其他信息。此外，这是对所做假设的验证。本文还提供了处理出版物中已知实验数据的示例。