| Title: | Find Corners in Digital Images with FAST-9 |
|---|---|
| Description: | An implementation of the "FAST-9" corner detection algorithm explained in the paper 'FASTER and better: A machine learning approach to corner detection' by Rosten E., Porter R. and Drummond T. (2008), available at <arXiv:0810.2434>. The package allows to detect corners in digital images. |
| Authors: | Jan Wijffels [aut, cre, cph], BNOSAC [cph], Julien Cayzac [ctb, cph] |
| Maintainer: | Jan Wijffels <[email protected]> |
| License: | BSD_2_clause + file LICENSE |
| Version: | 0.1.0 |
| Built: | 2024-11-11 04:44:18 UTC |
| Source: | https://github.com/bnosac/image |
An implementation of the "FAST-9" corner detection algorithm explained at <http://www.edwardrosten.com/work/fast.html>. The package allows to detect corners in digital images.
An implementation of the "FAST-9" corner detection algorithm explained at <http://www.edwardrosten.com/work/fast.html>.
image_detect_corners(x, threshold = 50L, suppress_non_max = FALSE)image_detect_corners(x, threshold = 50L, suppress_non_max = FALSE)
x |
a matrix of image pixel values in the 0-255 range. |
threshold |
positive integer where threshold is the threshold below which differences in luminosity between adjacent pixels are ignored. Think of it as a smoothing parameter. |
suppress_non_max |
logical |
as list of the found corners with the x/y locations
library(pixmap) imagelocation <- system.file("extdata", "chairs.pgm", package="image.CornerDetectionF9") image <- read.pnm(file = imagelocation, cellres = 1) x <- image@grey * 255 corners <- image_detect_corners(x, 80) plot(image) points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5) ## ## image_detect_corners expects a matrix as input ## if you have a jpg/png/... convert it to pgm first or take the r/g/b channel library(magick) x <- image_read(system.file("extdata", "hall.jpg", package="image.CornerDetectionF9")) x image <- image_data(x, channels = "Gray") image <- as.integer(image, transpose = TRUE) image <- drop(image) corners <- image_detect_corners(image, threshold = 80) plt <- image_draw(x) points(corners$x, image_info(x)$height - corners$y, col = "red", pch = 20, lwd = 0.5) dev.off() plt ## same but now converting to portable grey mab f <- tempfile(fileext = ".pgm") library(magick) x <- image_read(system.file("extdata", "hall.jpg", package="image.CornerDetectionF9")) x <- image_convert(x, format = "pgm", depth = 8) image_write(x, path = f, format = "pgm") image <- read.pnm(f, cellres = 1) corners <- image_detect_corners(image@grey * 255, 80) plot(image) points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5) file.remove(f)library(pixmap) imagelocation <- system.file("extdata", "chairs.pgm", package="image.CornerDetectionF9") image <- read.pnm(file = imagelocation, cellres = 1) x <- image@grey * 255 corners <- image_detect_corners(x, 80) plot(image) points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5) ## ## image_detect_corners expects a matrix as input ## if you have a jpg/png/... convert it to pgm first or take the r/g/b channel library(magick) x <- image_read(system.file("extdata", "hall.jpg", package="image.CornerDetectionF9")) x image <- image_data(x, channels = "Gray") image <- as.integer(image, transpose = TRUE) image <- drop(image) corners <- image_detect_corners(image, threshold = 80) plt <- image_draw(x) points(corners$x, image_info(x)$height - corners$y, col = "red", pch = 20, lwd = 0.5) dev.off() plt ## same but now converting to portable grey mab f <- tempfile(fileext = ".pgm") library(magick) x <- image_read(system.file("extdata", "hall.jpg", package="image.CornerDetectionF9")) x <- image_convert(x, format = "pgm", depth = 8) image_write(x, path = f, format = "pgm") image <- read.pnm(f, cellres = 1) corners <- image_detect_corners(image@grey * 255, 80) plot(image) points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5) file.remove(f)