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copied!<p>What would be slow is the call to <code>GetPixel</code>. If you want to call it only as needed, you could use something like this:</p> <pre><code>open System.Drawing let lazyPixels (image:Bitmap) = let Width = image.Width let Height = image.Height let pixels : Lazy<byte>[,,] = Array3D.zeroCreate 3 Width Height for i = 0 to Width-1 do for j = 0 to Height-1 do let point = lazy image.GetPixel(i,j) pixels.[0,i,j] <- lazy point.Value.R pixels.[1,i,j] <- lazy point.Value.G pixels.[2,i,j] <- lazy point.Value.B pixels </code></pre> <p><code>GetPixel</code> will be called at most once for every pixel, and then reused for the other components.</p> <p>Another way of approaching this problem would be to do a bulk-load of the entire image. This will be a lot quicker than calling <code>GetPixel</code> over and over again.</p> <pre><code>open System.Drawing open System.Drawing.Imaging let pixels (image:Bitmap) = let Width = image.Width let Height = image.Height let rect = new Rectangle(0,0,Width,Height) // Lock the image for access let data = image.LockBits(rect, ImageLockMode.ReadOnly, image.PixelFormat) // Copy the data let ptr = data.Scan0 let stride = data.Stride let bytes = stride * data.Height let values : byte[] = Array.zeroCreate bytes System.Runtime.InteropServices.Marshal.Copy(ptr,values,0,bytes) // Unlock the image image.UnlockBits(data) let pixelSize = 4 // <-- calculate this from the PixelFormat // Create and return a 3D-array with the copied data Array3D.init 3 Width Height (fun i x y -> values.[stride * y + x * pixelSize + i]) </code></pre> <p>(adopted from the C# sample on <a href="http://msdn.microsoft.com/en-us/library/5ey6h79d.aspx" rel="nofollow noreferrer" title="Bitmap.LockBits Method (Rectangle, ImageLockMode, PixelFormat)"><code>Bitmap.LockBits</code></a>)</p>

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