Automated Color Misalignment Correction for Close-Range and Long-Range Hyper-Resolution Multi-Line CCD Images

Surveillance and inspection have an important role in security and industry applications and are often carried out with line-scan cameras. The advantages of line-scan cameras include hyper-resolution (larger than 50 Megapixels), continuous image generation, and low cost, to mention a few. However, due to the physical separation of line CCD sensors for the red (R), green (G), and blue (B) color channels, the color images acquired by multi-line CCD cameras intrinsically exhibit a color misalignment defect, such that the edges of objects in the scene are separated by a certain number of pixels in the R, G, B color planes in the scan direction. This defect, if not corrected properly, can severely degrade the quality of multi-line CCD images and hence impairs the functionality of the cameras. Current techniques for correcting such color misalignments are typically not fully automated, which is undesirable in applications such as inspection and surveillance that depend on fast unmanned responses. This chapter introduces an algorithm to automatically correct the color misalignments in multi-line CCD images for rotational scans as well as for translational scans. Results are presented for two different configurations of multi-line CCD imaging systems: (a) a close-range multi-line CCD imaging system for inspection applications and (b) a long-range imaging system for surveillance applications. Experimental results show that the two imaging systems are able to acquire hyper-resolution images and the color misalignment correction algorithm can automatically and accurately correct those images for their respective applications.