imgprocexperiments.fs

namespace LangexplrExperiments
open System.Drawing
open System.Drawing.Imaging
open Microsoft.FSharp.Math

module ImageProcExperiments = begin
  
  let Load24BitImageData (fileName:string) =
     using(new Bitmap(fileName)) 
          (fun bm ->
              if bm.PixelFormat <> PixelFormat.Format24bppRgb then
                 raise (new System.NotSupportedException("Bitmap not supported"))
                 
              let rect = new Rectangle(0,0,bm.Width,bm.Height)
              
              let bmpData = bm.LockBits(rect,System.Drawing.Imaging.ImageLockMode.ReadOnly,bm.PixelFormat)
              
              let result : byte array = Array.create (bmpData.Height*bmpData.Stride) (byte(0))
              System.Runtime.InteropServices.Marshal.Copy(bmpData.Scan0, result, 0, bmpData.Height*bmpData.Stride);               
              bm.UnlockBits(bmpData)
              
              bmpData.Height,bmpData.Stride,result
          )
          
  let Save24BitImageData (width:int,height:int,data : byte array,fileName:string) =
     using(new Bitmap(width,height,PixelFormat.Format24bppRgb)) 
          (fun bm -> 
                              
              let rect = new Rectangle(0,0,bm.Width,bm.Height)
              
              let bmpData = bm.LockBits(rect,System.Drawing.Imaging.ImageLockMode.WriteOnly,bm.PixelFormat)              
              System.Runtime.InteropServices.Marshal.Copy(data,0,bmpData.Scan0,  Array.length data);               
              bm.UnlockBits(bmpData)
              
              bm.Save(fileName,ImageFormat.Jpeg)
          )
          
  let SeparateChannel( width,height,data : byte array,channel) =
     let newWidth = (width/3)
     let result = Array2D.create height newWidth (byte(0))
     Array.iteri (fun i _ -> if ((i+3) % 3 = 0) then
                                result.[i/(3*newWidth),(i/3)%newWidth] <- data.[i + channel]
                             else
                                ())
                  data
     result
 
  let MatrixToArray( width,height,data,channel) =
     let newWidth = width*3
     let result = Array.create (height*width*3) (byte(0))
     Array2D.iteri (fun i j d ->                      
                        result.[(newWidth*i)+((j*3) + channel)] <- d) data
     result
 
  let FlattenUsingOneChannel( data : byte array,channel) =
     Array.iteri (fun i _ -> if (i % 3 = 0) then
                                let newData = data.[i+channel]
                                data.[i] <- newData
                                data.[i+1] <- newData
                                data.[i+2] <- newData) 
                 data
     data
     
     
  let DFT (matrix:byte[,]) (col:int) (row:int) = 
      let c = 1.0/float(Array2D.length1 matrix)      
      let mutable result = Complex.zero
      for y = 0 to Array2D.length1 matrix do
        for x = 0 to Array2D.length2 matrix do
           let exponent = float(-1)*  Complex.onei * float(2) * float(col*x + row*y) 
           result <- result + float(matrix.[row,col]) * Complex.Exp( (1.0/float(Array2D.length1 matrix) * exponent  ))             
      c*result
      
  let imageDFT matrix = 
      Array2D.mapi (fun i j _ -> DFT matrix  j i) matrix
end