This is a very interesting question.

A strong motivation for considering Multilevell Image Segmentation (MIS) is the rich sources forms of hyperspectral images. For example, hyperspectral remote sensing images contain hundreds of data channels.   A detailed MIS solution 

https://www.researchgate.net/publication/261634230_Multilevel_Image_Segmentation_Based_on_Fractional-Order_Darwinian_Particle_Swarm_Optimization

A comparison of image segmentation methods that includes MIS is given in

https://www.researchgate.net/publication/272484780_Image_Segmentation_Methods_A_Comparative_Study

Article Multilevel Image Segmentation Based on Fractional-Order Darw...

Article Image Segmentation Methods: A Comparative Study

hi Mr Peter

Thanks. I will study these papers.

thanks:)

Dear Atefeh Ghanbari, Bat algorithm is a recent metaheuristic based on so-called echolocation of the bats. In this algorithm, bats detect prey and avoid the obstacles by using the echolocation. Bat algorithm was successfully applied to a number of very different problems like large-scale optimization problems, global engineering optimization, fuzzy clustering, parameter estimation in dynamic biological systems, multiobjective optimization, image matching, economic load and emission dispatch problems, data mining, scheduling problems, neural networks, and phishing website detection.

In the bat algorithm, bats navigate by using time delay from emission to the reflection. The pulse rate can be simply determined in the range from 0 to 1, where 0 means that there is no emission and 1 means that the bat's emitting is at maximum. Apart from the control parameters, such as the population size and maximum iteration number which are common control parameters for all nature inspired algorithms, the BA has few important parameters such as frequency tuning parameter similar to the key feature used in the PSO and HS, parameter for automatically zooming into a region where the promising solutions have been found, and the control parameter for automatically switching from exploration to exploitation. 

hi Mr Christo Ananth

thanks, but I just want advantages of Multilevel Image Segmentation.

In multilevel image segmentation you are able to segment images into several part instead of twp part. So if you have more than 1 object you can not segment all object by using bi-level segmentation but multilevel can be helpful in this case. In the other hand determine the optimum number of segments is handicap in this subject.

I agree with Taymaz R.Farshi

++

for the matter of the optimum object, we can use

gray histogram, red histogram, green histogram and blue histogram, using valley and peak characteristic analysis