Advanced Imaging Processing for Infrared Camera
Infrared focal plane array (IRFPA) sensors are widely used in the fields of aviation, industry, agriculture, medicine, and scientific research. However, the nonuniformity, produced by mismatches during the fabrication process of the IRFPA can considerably degrade the spatial resolution and temperature resolvability, since it results in a fixed pattern noise (FPN) that is superimposed on the observed images. Therefore, nonuniformity correction (NUC), being an indispensable key step, is applied to nearly all of the IRFPA-based engineering applications. Further, what makes the problem worse is that the nonuniformity varies over time and is closely related to external conditions, which results in the failure of traditional reference-based NUC methods. In order to solve this problem, scene-based nonuniformity correction (SBNUC) must be applied.
Scene-based Nonuniformity Correction (SBNUC)
HDR IR Image Display and Detail Enhancement (DDE)
Histogram equalization is a popular technique for enhancing image contrast. However, it tends to change the brightness of an image and hence leads to annoying artifacts. We have proposed a novel extension of histogram equalization referred to as Range Limited Bi-Histogram Equalization (RLBHE). First, RLBHE divides the input histogram into two independent sub-histograms by a threshold that minimizes the intra-class variance. This is done in order to effectively separate the objects from the background. Then, range of the equalized image is calculated to yield minimum absolute mean brightness error between the original image and the equalized one. The proposed RLBHE can achieve visually more pleasing contrast enhancement while maintaining the input brightness.