एफ #, हिस्टोग्राम को संरेखित करके छवि के विपरीत को बढ़ाता है

// Learn more about F# at http://fsharp.org
open OpenCvSharp
open Microsoft.FSharp.NativeInterop

//     
let getHistogram (mat: Mat) =
    let hx = Array.zeroCreate<int> 256
    mat.ForEachAsByte(fun value _ ->
                           let v = int (NativePtr.get value 0)
                           hx.[v] <- hx.[v] + 1)
    hx

//      
let getCdx hx =
    hx |> Array.mapi (fun x _ -> if x > 0 then hx.[0..(x-1)] |> Array.sum else 0)

//     
let drawHistogramAndCdx hx cdx (mat: Mat) =
    let histoWidth = 256
    let histoHeight = 256

    //     
    let cdxMax = cdx |> Array.max
    //      ( )
    //    
    let cdxK = float(histoHeight)/float(cdxMax)

    let histMax = hx |> Array.max
    let histK = float(histoHeight)/float(histMax)

    let histMat = new Mat(histoWidth, histoHeight, MatType.CV_8UC4)
    hx
    |> Array.iteri (fun x v ->
                        let histDy = int(float(v)*histK)
                        let cdxDy = int(float(cdx.[x])*cdxK)
                        //   h(x)
                        mat.Line(x, histoHeight-1, x, histoHeight-1-histDy, Scalar.White)
                        //    cdx(x)
                        mat.Circle(x, histoHeight-cdxDy, 1, Scalar.Blue))

[<EntryPoint>]
let main argv =

    let histoWidth = 256
    let histoHeight = 256

    let src = Cv2.ImRead("cat.jpg", ImreadModes.Grayscale)
    let equalizeImage = new Mat(src.Rows, src.Cols, MatType.CV_8UC1)

    // calculate histogram h(x)
    let hx = getHistogram src

    // calculate cdf(x) = h(0) + h(1) + .. + h(x)
    let cdx = getCdx hx

    // draw histogram
    let histMat = new Mat(histoWidth, histoHeight, MatType.CV_8UC4)
    drawHistogramAndCdx hx cdx histMat

    // equalize the histogram
    let cdxMin = cdx |> Array.filter (fun v -> v > 0) |> Array.min
    let totalPixels = src.Rows * src.Cols

    for y in 0..src.Rows do
        for x in 0..src.Cols do
            let s = int(src.At<byte>(y, x))
            let fx = (float(cdx.[s]) - float(cdxMin))/(float(totalPixels - 1))*255.
            //equalizeImage.Set<Scalar>(y, x, new Scalar(double(fx)))
            equalizeImage.Circle(x, y, 1, new Scalar(double(fx)))

    // calculate equalize histogram
    let hx2 = getHistogram equalizeImage
    let cdx2 = getCdx hx2

    let histMat2 = new Mat(histoWidth, histoHeight, MatType.CV_8UC4)
    drawHistogramAndCdx hx2 cdx2 histMat2

    // opencv equalize histogram
    let opencCVImage = new Mat(src.Rows, src.Cols, MatType.CV_8UC1)
    let in1 = InputArray.Create(src)
    let in2 = OutputArray.Create(opencCVImage)

    Cv2.EqualizeHist(in1, in2)

    // get opencv histogram
    let hx3 = getHistogram opencCVImage
    let cdx3 = getCdx hx3

    let histMat3 = new Mat(histoWidth, histoHeight, MatType.CV_8UC4)
    drawHistogramAndCdx hx3 cdx2 histMat3

    // show results
    use w1 = new Window("original image", src)
    use w2 = new Window("original histogram", histMat)

    use w3 = new Window("custom equalize image", equalizeImage)
    use w4 = new Window("custom equalize histogram", histMat2)

    use w5 = new Window("opencv equalize image", opencCVImage)
    use w6 = new Window("opencv equalize histogram", histMat3)

    Cv2.WaitKey() |> ignore

    0 // return an integer exit code