# Distance for images Calculates distance matrix for a sample of images using the minimax metric. This fucntion can be seen as a wrapper of a sequential call of `images2curves` and `dist.curves`. ```r dist.images(images, verbosity = 0L) ``` ## Arguments - `images`: A 3-dimensional array with each slice (matrix in first two dimensions) corresponding to an image. Each (eps-strictly) positive entry is regarded as an occupied pixel (one), otherwise it is regarded as an empty pixel, of an image. - `verbosity`: Level of reporting messages, the higher the more progress reports are printed, set `0` (default) for no messages. ## Returns A matrix `dim(images)[3] x dim(images)[3]` with each entry being the distance between two images. ## Examples ```r library(curveDepth) # Pixel-grid filling function for an image plotGridImage <- function(dims){ redDims1 <- dims[1] - 1 redDims2 <- dims[2] - 1 for (i in 1:(dims[1] - 1)){ lines(c(i / redDims1 - 0.5 / redDims1, i / redDims1 - 0.5 / redDims1), c(0 - 0.5 / redDims2, 1 + 0.5 / redDims2), lwd = 1, lty = 3, col = "lightgray") lines(c(0 - 0.5 / redDims1, 1 + 0.5 / redDims1), c(i / redDims2 - 0.5 / redDims2, i / redDims2 - 0.5 / redDims2), lwd = 1, lty = 3, col = "lightgray") } rect(0 - 0.5 / redDims1, 0 - 0.5 / redDims2, 1 + 0.5 / redDims1, 1 + 0.5 / redDims2) } # Load two Sevens and one One, and plot them data("mnistShort017") # First Seven firstSevenDigit <- mnistShort017$`7`[, , 5] image(as.matrix(rev(as.data.frame(firstSevenDigit))), col = gray((255:0) / 256), asp = 1, xlim = c(0 - 1 / 27, 1 + 1 / 27), ylim = c(0 - 1 / 27, 1 + 1 / 27)) plotGridImage(dim(firstSevenDigit)[1:2]) # Second Seven secondSevenDigit <- mnistShort017$`7`[, , 6] image(as.matrix(rev(as.data.frame(secondSevenDigit))), col = gray((255:0) / 256), asp = 1, xlim = c(0 - 1 / 27, 1 + 1 / 27), ylim = c(0 - 1 / 27, 1 + 1 / 27)) plotGridImage(dim(secondSevenDigit)[1:2]) # A One aOneDigit <- mnistShort017$`1`[, , 1] image(as.matrix(rev(as.data.frame(aOneDigit))), col = gray((255:0) / 256), asp = 1, xlim = c(0 - 1 / 27, 1 + 1 / 27), ylim = c(0 - 1 / 27, 1 + 1 / 27)) plotGridImage(dim(aOneDigit)[1:2]) # Caculate distances between all the images threeDigits <- array(NA, dim = c(nrow(firstSevenDigit), ncol(firstSevenDigit), 3)) threeDigits[, , 1] <- firstSevenDigit threeDigits[, , 2] <- secondSevenDigit threeDigits[, , 3] <- aOneDigit distMatrix <- dist.images(threeDigits) # Print distance matrix print(distMatrix) ``` ## References Lafaye De Micheaux, P., Mozharovskyi, P. and Vimond, M. (2018). Depth for curve data and applications.

dist.images function