image_textlines_astar {image.textlinedetector}

Text Line Segmentation based on the A* Path Planning Algorithm

Description

Text Line Segmentation based on the A* Path Planning Algorithm

Usage

image_textlines_astar(x, morph = FALSE, step = 2, mfactor = 5, trace = FALSE)

Arguments

x

an object of class magick-image

morph

logical indicating to apply a morphological 5x5 filter

step

step size of A-star

mfactor

multiplication factor in the cost heuristic of the A-star algorithm

trace

logical indicating to show the evolution of the line detection

Value

a list with elements

• n: the number of lines found

• overview: an opencv-image of the detected areas

• paths: a list of data.frame's with the x/y location of the baseline paths

• textlines: a list of opencv-image's, one for each rectangular text line area

• lines: a data.frame with the x/y positions of the detected lines

Examples

library(opencv)
library(magick)
library(image.textlinedetector)
path   <- system.file(package = "image.textlinedetector", "extdata", "example.png")
img    <- image_read(path)
img    <- image_resize(img, "x1000")
areas  <- image_textlines_astar(img, morph = TRUE, step = 2, mfactor = 5, trace = TRUE)
areas  <- lines(areas, img)
areas$n
areas$overview
areas$lines
areas$textlines[[2]]
areas$textlines[[4]]
combined <- lapply(areas$textlines, FUN=function(x) image_read(ocv_bitmap(x)))
combined <- do.call(c, combined)
combined
image_append(combined, stack = TRUE)



plt <- image_draw(img)
lapply(areas$paths, FUN=function(line){
  lines(x = line$x, y = line$y, col = "red")  
})
dev.off()
plt