Infrared spectroradiometer based on light splitting of gradual filter

The invention discloses an infrared spectroradiometer based on light splitting of a gradual filter. A light chopper is arranged behind an incident lens. A variable diaphragm is arranged behind the light chopper. The gradual filter is arranged behind the variable diaphragm. A first focusing lens group is arranged between the variable diaphragm and the gradual filter. An infrared detector is arranged behind the gradual filter. A second focusing lens group is arranged between the gradual filter and the infrared detector. Light form the incident lens forms a first focusing point by the light chopper, the variable diaphragm is arranged at the first focusing point, the light passes through the variable diaphragm and forms a second focusing point through the first focusing lens group, the gradual filter is arranged at the second focusing point, the light passes through the gradual filter and forms a third focusing point through the second focusing lens group, the infrared detector is arranged at the third focusing point, and the first focusing point, the second focusing point and the third focusing point are arranged on the same axis. According to the invention, the visual field control effect of the variable diaphragm is ensured, the assembling and adjusting difficulty is lowered, and the focusing effect is improved.