RGB Color Thresholding

Image Thresholding By Channel

The rubics cube with distinctly colored pieces are represented by pixels that are functions of Red, Green and Blue channels.

https://medtraf.shinyapps.io/Products

This leaning tool allows user to look at the effect of thresholding by color channel.

 shinyUI(pageWithSidebar(
  headerPanel("Thresholding by Color Channel"),
  sidebarPanel(
    sliderInput('hp', 'Threshold',value = .01, min = 0, max = 1, step = 0.01),
    sliderInput('ch', 'Channel',value = 1, min = 1, max = 3, step =1)
  ),
  mainPanel(
    img(src='cube.jpg', align = "left"),
    plotOutput('myHist')
  )
))

Test

library(UsingR)
data(galton)
data(mtcars)
library(jpeg)
library(raster)
shinyServer(
  function(input, output) {
      output$myHist <- 
      renderPlot({
      hp <- input$hp
      ch<-input$ch
      generatePlot <- function (data, plotName,f) {
        below = which(data<f) 
        data[below] <- NA
        rv1 <- raster(data)
        plotData <- spplot(rv1, scales = list(draw = TRUE), col.regions=heat.colors(1, alpha=1), main=plotName)
        return(plotData)
      }
      m=readJPEG('cube.jpg', native = FALSE)[,,ch]
      plotData = generatePlot(m,'Thesholded Rubics Cube',hp)
      print(plotData)
    }
    )
  }
)