Challenges: Flickering effect
1. Overview
The "sunlight flicker" which is cause by non-uniform illumination towards submerged objects. This considered a major "visual" disturbance to computer vision as original visual properties of the object such as colour and shape. Below is a simple example of how sunlight flicker:
2. Homomorphic Filter
It is a generally used in signal and image processing to remove multiplicative noise in this case those flickering effect. It effectively normalizes brightness across all pixels and increase contrast. However, post-processing is needed since it may cause some blurring in the attempt to normalize the brightness. Though the original implementation work on the frequency domain, our implementation only operates on image domain. Here is a direct comparison before and after applying the filter:
You can find the relevant implementation here
References
1. webee.technion.ac.il/~yoav/publications/flicker_oceans.pdf2. http://webee.technion.ac.il/~yoav/publications/tflick5.pdf
