J . -M . Deniel et al .: Radioprotection 2024 , 59 ( 3 ), 225 – 234 231
Table 1 . Blackbody temperature estimation , in ° C . “ Blackbody temperature ” refers to the setting of the device . “ Estimated temperatures ” result from applying our method to the picture colors in a 9 9 pixel region corresponding to the center of the blackbody opening .
Blackbody temperature
Estimated temperature
|
Mean |
Min |
Max |
800 ° C |
856 |
812 |
899 |
900 ° C |
943 |
899 |
981 |
1000 ° C |
1031 |
981 |
1062 |
1100 ° C |
1131 |
1082 |
1160 |
1200 ° C |
1227 |
1180 |
1278 |
1300 ° C |
1326 |
1298 |
1357 |
Fig . 10 . Wall temperature estimates inside the INRS metal furnace . Temperatures are shown in interpolated false colors : for example , blue corresponds to 700 ° C , violet corresponds to 1100 ° C .
estimated temperatures from the colors in a 9 9 pixel area at the center of the blackbody opening ( see Tab . 1 ).
In addition , Figure 9 illustrates the behavior of the method over the entire blackbody opening , which radiance uniformity is not perfect . Values in Table 1 correspond to pixels in the center of pictures in Figure 9 .
3.2 Estimated temperature of materials inside the metal furnace
Pictures were taken of the metal furnace set at 800 ° Cto 100 ° C every 100 ° C , plus 1140 ° C . Note that at 1140 ° C , the pixels at the heating coils were saturated . Figure 10 illustrates the application of our method to all these pictures to estimate the temperature of the furnace cavity and samples inside .
To complete these results , we choose to retrieve temperature estimates in 9 9 pixel picture areas in the picture of the furnace set at 1100 ° C ( see Fig . 1 ). We chose this furnace temperature as the most exposing of the analyzed situations , without any saturated pixels in the picture . In this picture , four letters correspond to 9 9 pixel areas :
* The GR28 firebrick , that is a cellular material
* A dense silica firebrick in the least cooling part of the cavity , close to the furnace air probe
* A dense silica firebrick next to a heating coil in the back of the cavity
* A heating coil , as these are the hottest parts in the furnace .
For each of these areas , we indicate the mean , min and max estimated temperatures in Table 2 .
Lastly , whatever the furnace temperature , almost only graphite ( see Fig . 6 ) was associated with pixels of interest . A few percent were associated with the 1400 ° C blanket ( see Fig . 5 ). This is because these two materials are among � the most emissive and are retained as the worst cases in the v r ; b r to m