The remnant stray radiation may cause image anomaly after taking suppressiones of optical and mechanical design in infrared optical system

Such as movement of lense during zooning may change the solid angle of narcissys

which caused narcissus variation in the system. To minimize the effects

we provided a direct and fast method for suppressing the narcissus variation by two point non-uniformity correction. As an example

the stray radiation analysis and suppression of an infrared zoom optical system is presented. The result confirms that the method can improve image anomaly caused by remnant stray radiation .The disadvantage is reduction the contrast of the image.