Anchor-Free Braille Character Detection Based on Edge Feature in Natural Scene Images

Algorithm 1

The process of predicting Braille character rectangles.

	Input: edge region matrix M (H × W), the corresponding predict distance D (4 × H × W)
	Output: the list of Braille character rectangles R
(1)	R = [] iNum = 0 Rcol = [] #Initial
(2)	for each x in range (W)
(3)	Rcol (x) = []
(4)	for each y in range (H)
(5)	if M (x,y) ≥ 0.8 then
(6)	d1 = D (x,y)[1] d2 = D (x,y) [2] d3 = D (x,y) [3] d4 = D (x,y) [4]
(7)	x1 = x–d1 x2 = x + d2 y1 = y–d3 y2 = y + d4
(8)	Rtemp = (x1, y1, x2, y2)
(9)	Rcol (x) = NMS (Rcol (x), Rtemp) #run the NMS algorithm by column
(10)	endif
(11)	endfor
(12)	endfor
(13)	R = NMS (Rcol) #run the NMS algorithm
(14)	return R