Table 2.

Symbols and descriptions used in our algorithm.

Symbol	Description
$D_{Img}$	Test image
PCNN	Pulse Coupled Neural Network
LTP	Local Ternary Pattern
$G_{Img}$	Gray-scale image
$I{R}_{seg}$	Resultant image
LDoF	Low Depth of Filed
MCC	Matthew’s Correlation-Coefficient
DSC	Dice-Similarity-Coefficient
JCM	Jaccard-Coefficient Measure
$G_{Img\left(Rgn\right)}$	Gray-scale image region
Max${}_{F\left(Rgn\right)}$	Maximum frequency region
Min${}_{F\left(Rgn\right)}$	Minimum frequency region
Mean${}_{F\left(Rgn\right)}$	Average frequency region
$D_{Img\left(xy\right)}$	The pixel coordinate (x,y) in the defocused image
${Td}_{LTP}$	Thresholded LTP value
$B_{LTP}$	Binary segmentation of LTP algorithm
${\mathcal{M}}_{Edge}$	Resultant edge map of PCNN
f	The sequence of firing matrix that records each firing order of pixel
${\mathbb{P}}_{Con}$	Pixel-connectivity matrix
$B_{seg}$	Binary segmented output
${\mathbb{C}}_{seg}$	Color segmented output
$W_{con}$	Connecting-weight matrix
$\delta$	Connecting coefficient of strength
${\Im }_{\mathrm{E}}$	Dynamic-threshold coefficient
$ϵ$	Dynamic-strength coefficient
$F_{\mathrm{E}}$	Decay-factor
$M_{LF}$	Gray-scale mean values of low scale frequency
$M_{MF}$	Gray-scale mean values of mid scale frequency
$M_{HF}$	Gray-scale mean values of high scale frequency
Td${}_{min}$	Threshold value along with minimum limit
$\mathbb{C}$	Criteria for judgment
$\gamma$	Dynamic-threshold matrix
EDAS	Evaluation Based on Distance from Average Solution