Image processing

Image dimensions:

library(tidyverse)
library(jpeg)
library(mdatools)
library(plotly)



beef = readJPEG('beef.jpg')
dim(beef)

[1] 492 681   3

Channels

par(mfrow= c(2,2))
d = mda.im2data(beef)
imshow(d, 1:3, main = 'RGB')
imshow(d, 1, main = 'RED', colmap = 'gray')

imshow(d, 2, main = 'GREEN', colmap = 'gray')
imshow(d, 3, main = 'BLUE', colmap = 'gray')

pc = pca(d)
pc = selectCompNum(pc, 2)

plotScores(pc, cex= 0.1)

imshow(pc$calres$scores, 1)

library(gatepoints)

score = pc$calres$scores[,1:2]

x11()
mdaplot(score, cex= 0.1)
selectedPoints <- fhs(score)

Mark region on plot.

selection = selectedPoints[1:length(selectedPoints)] %>% as.numeric()

pc = pca(d, exclrows = selection)

plotScores(pc, cex= 0.1)

NA
NA

imshow(pc$calres$scores)

x11()
mdaplot(pc$calres$scores[-selection,1:2], show.lines = c(0,0), cex = 0.1)
selectedPoints2 <- fhs(pc$calres$scores[,1:2])

Mark region on plot.

selection2 = selectedPoints2[1:length(selectedPoints2)] %>% as.numeric()

a = c(1:nrow(d))
a = a[-selection2] %>% as.numeric()

pc1 = pca(d, exclrows = a)

plotScores(pc1, cex= 0.1)

imshow(pc1$calres$scores,1)

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NA

e = mda.setimbg(d, d[,1] < 0.88)

imshow(e,2)

Overall = length(d)
Sample = length(d)-length(selection)
Marbling = length(selection2)

dftot = data.frame('Pixel_count' = c(Overall, Sample, Marbling))
rownames(dftot) = c('Overall', 'Sample', 'Marbling')

dftot = cbind(dftot, 'prc' = c(dftot$Pixel_count/Overall*100)) %>%   round(digits = 2)%>% 
  mutate(sample_prc = c('-','-', round((Marbling/Sample*100), digits = 2) ))  %>%
  mutate(prc = paste(prc, '%', sep = ''))
      
dftot$sample_prc[3] = paste(dftot$sample_prc[3], '%', sep = '')
  
dftot %>% kable() %>% kable_styling('striped', full_width = F)

	Pixel_count	prc	sample_prc
Overall	1005156	100%	-
Sample	851356	84.7%	-
Marbling	22799	2.27%	2.68%

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