R/CentroidBand.r

In jjlynch2/CentroidBanding: Centroid Banding from three-dimensional models

#' Centroid Band Extraction
#' 
#' @param data A list of matrices of XYZ point clouds
#' @param pc Align along principal components before extracting
#' @param threshold Metric for band thickness relative to the point cloud scale
#'
#' @keywords CentroidBand
#' @export
#' @examples
#' CentroidBand(data = pointclouds, pc = TRUE, threshold = 4)

CentroidBand <- function(data = NULL, pc = TRUE, threshold = 4) {
	pointcloud_list <- list()
	for(i in 1:length(data)) {
		#align along principal components
		if(pc) {
			pointcloud <- CentroidBanding::pca_align(data[[i]])
		}
		else {
			pointcloud <- data[[i]]
		}

		#calculate centroid
		centroid <- apply(pointcloud, 2, mean)

		#first band
		t1 <- pointcloud[pointcloud[,1] <= centroid[1]+threshold, ]
		band_1 <- t1[t1[,1] >= centroid[1]-threshold, ]

		#second band
		t2 <- pointcloud[pointcloud[,2] <= centroid[2]+threshold, ]
		band_2 <- t2[t2[,2] >= centroid[2]-threshold, ]

		#third band
		t3 <- pointcloud[pointcloud[,3] <= centroid[3]+threshold, ]
		band_3 <- t3[t3[,3] >= centroid[3]-threshold, ]

		#row binds into a single matrix
		pointcloud_list[[i]] <- unique(rbind(band_1, band_2, band_3))
	}
	return(pointcloud_list)
}