/// <summary>
/// 从指定的托管内存图片转换成非托管内存图片
/// </summary>
/// <param name="imageData">锁定的托管内存图片</param>
/// <returns>Returns new unmanaged image, which is a copy of source managed image.</returns>
/// <remarks><para>The method creates an exact copy of specified managed image, but allocated
/// in unmanaged memory. This means that managed image may be unlocked right after call to this
/// method.</para></remarks>
/// <exception cref="UnsupportedImageFormatException">Unsupported pixel format of source image.</exception>
public static UnmanagedImage FromManagedImage(BitmapData imageData)
{
PixelFormat pixelFormat = imageData.PixelFormat;
// check source pixel format
if (
(pixelFormat != PixelFormat.Format8bppIndexed) &&
(pixelFormat != PixelFormat.Format16bppGrayScale) &&
(pixelFormat != PixelFormat.Format24bppRgb) &&
(pixelFormat != PixelFormat.Format32bppRgb) &&
(pixelFormat != PixelFormat.Format32bppArgb) &&
(pixelFormat != PixelFormat.Format32bppPArgb) &&
(pixelFormat != PixelFormat.Format48bppRgb) &&
(pixelFormat != PixelFormat.Format64bppArgb) &&
(pixelFormat != PixelFormat.Format64bppPArgb))
{
throw new UnsupportedImageFormatException("Unsupported pixel format of the source image.");
}
// allocate memory for the image
IntPtr dstImageData = System.Runtime.InteropServices.Marshal.AllocHGlobal(imageData.Stride * imageData.Height);
UnmanagedImage image = new UnmanagedImage(dstImageData, imageData.Width, imageData.Height, imageData.Stride, pixelFormat);
UnmanagedMemoryHelper.CopyUnmanagedMemory(dstImageData, imageData.Scan0, imageData.Stride * imageData.Height);
image.mustBeDisposed = true;
return(image);
}
/// <summary>
/// 拷贝该非托管图片
/// </summary>
/// <param name="destImage">将非托管图片拷贝至的目标图片位置</param>
/// <remarks><para>The method copies current unmanaged image to the specified image.
/// Size and pixel format of the destination image must be exactly the same.</para></remarks>
/// <exception cref="InvalidImagePropertiesException">Destination image has different size or pixel format.</exception>
public void Copy(UnmanagedImage destImage)
{
if (
(width != destImage.width) || (height != destImage.height) ||
(pixelFormat != destImage.pixelFormat))
{
throw new InvalidImagePropertiesException("Destination image has different size or pixel format.");
}
if (stride == destImage.stride)
{
// copy entire image
UnmanagedMemoryHelper.CopyUnmanagedMemory(destImage.imageData, imageData, stride * height);
}
else
{
unsafe
{
int dstStride = destImage.stride;
int copyLength = (stride < dstStride) ? stride : dstStride;
byte *src = (byte *)imageData.ToPointer();
byte *dst = (byte *)destImage.imageData.ToPointer();
// copy line by line
for (int i = 0; i < height; i++)
{
UnmanagedMemoryHelper.CopyUnmanagedMemory(dst, src, copyLength);
dst += dstStride;
src += stride;
}
}
}
}
/// <summary>
/// Apply filter to an unmanaged image or its part.
/// </summary>
///
/// <param name="image">Unmanaged image to apply filter to.</param>
/// <param name="rect">Image rectangle for processing by the filter.</param>
///
/// <remarks>The method applies the filter directly to the provided source image.</remarks>
///
/// <exception cref="UnsupportedImageFormatException">Unsupported pixel format of the source image.</exception>
///
public void ApplyInPlace(UnmanagedImage image, Rectangle rect)
{
// check pixel format of the source image
CheckSourceFormat(image.PixelFormat);
// validate rectangle
rect.Intersect(new Rectangle(0, 0, image.Width, image.Height));
// process the filter if rectangle is not empty
if ((rect.Width | rect.Height) != 0)
{
// create a copy of the source image
int size = image.Stride * image.Height;
IntPtr imageCopy = MemoryManager.Alloc(size);
UnmanagedMemoryHelper.CopyUnmanagedMemory(imageCopy, image.ImageData, size);
// process the filter
ProcessFilter(
new UnmanagedImage(imageCopy, image.Width, image.Height, image.Stride, image.PixelFormat),
image, rect);
MemoryManager.Free(imageCopy);
}
}
/// <summary>
/// 将非托管图片转换成托管图片
/// </summary>
/// <param name="makeCopy">是否拷贝一份新的非托管内存</param>
/// <returns>Returns managed copy of the unmanaged image.</returns>
/// <remarks><para>If the <paramref name="makeCopy"/> is set to <see langword="true"/>, then the method
/// creates a managed copy of the unmanaged image, so the managed image stays valid even when the unmanaged
/// image gets disposed. However, setting this parameter to <see langword="false"/> creates a managed image which is
/// just a wrapper around the unmanaged image. So if unmanaged image is disposed, the
/// managed image becomes no longer valid and accessing it will generate an exception.</para></remarks>
public Bitmap ToManagedImage(bool makeCopy)
{
Bitmap dstImage = null;
if (!makeCopy)
{
dstImage = new Bitmap(width, height, stride, pixelFormat, imageData);
if (pixelFormat == PixelFormat.Format8bppIndexed)
{
Gimela.Media.Imaging.ImageHelper.SetGrayscalePalette(dstImage);
}
}
else
{
// create new image of required format
dstImage = (pixelFormat == PixelFormat.Format8bppIndexed) ?
Gimela.Media.Imaging.ImageHelper.CreateGrayscaleImage(width, height) :
new Bitmap(width, height, pixelFormat);
// lock destination bitmap data
BitmapData dstData = dstImage.LockBits(
new Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite, pixelFormat);
int dstStride = dstData.Stride;
int lineSize = Math.Min(stride, dstStride);
unsafe
{
byte *dst = (byte *)dstData.Scan0.ToPointer();
byte *src = (byte *)imageData.ToPointer();
if (stride != dstStride)
{
// copy image
for (int y = 0; y < height; y++)
{
UnmanagedMemoryHelper.CopyUnmanagedMemory(dst, src, lineSize);
dst += dstStride;
src += stride;
}
}
else
{
UnmanagedMemoryHelper.CopyUnmanagedMemory(dst, src, stride * height);
}
}
// unlock destination images
dstImage.UnlockBits(dstData);
}
return(dstImage);
}
/// <summary>
/// 克隆该非托管图片
/// </summary>
/// <returns>Returns clone of the unmanaged image.</returns>
/// <remarks><para>The method does complete cloning of the object.</para></remarks>
public UnmanagedImage Clone()
{
// allocate memory for the image
IntPtr newImageData = System.Runtime.InteropServices.Marshal.AllocHGlobal(stride * height);
UnmanagedImage newImage = new UnmanagedImage(newImageData, width, height, stride, pixelFormat);
newImage.mustBeDisposed = true;
UnmanagedMemoryHelper.CopyUnmanagedMemory(newImageData, imageData, stride * height);
return(newImage);
}
/// <summary>
/// Clone image.
/// </summary>
///
/// <param name="sourceData">Source image data.</param>
///
/// <returns>Clones image from source image data. The message does not clone pallete in the
/// case if the source image has indexed pixel format.</returns>
///
public static Bitmap Clone(BitmapData sourceData)
{
// get source image size
int width = sourceData.Width;
int height = sourceData.Height;
// create new image
Bitmap destination = new Bitmap(width, height, sourceData.PixelFormat);
// lock destination bitmap data
BitmapData destinationData = destination.LockBits(
new Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite, destination.PixelFormat);
UnmanagedMemoryHelper.CopyUnmanagedMemory(destinationData.Scan0, sourceData.Scan0, height * sourceData.Stride);
// unlock destination image
destination.UnlockBits(destinationData);
return(destination);
}
/// <summary>
/// Process new video frame.
/// </summary>
///
/// <param name="videoFrame">Video frame to process (detect motion in).</param>
///
/// <remarks><para>Processes new frame from video source and detects motion in it.</para>
///
/// <para>Check <see cref="MotionLevel"/> property to get information about amount of motion
/// (changes) in the processed frame.</para>
/// </remarks>
///
public unsafe void ProcessFrame(UnmanagedImage videoFrame)
{
lock (sync)
{
// check background frame
if (backgroundFrame == null)
{
// save image dimension
width = videoFrame.Width;
height = videoFrame.Height;
// alocate memory for background frame
backgroundFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
frameSize = backgroundFrame.Stride * height;
// convert source frame to grayscale
Grayscale.CommonAlgorithms.BT709.Apply(videoFrame, backgroundFrame);
return;
}
// check image dimension
if ((videoFrame.Width != width) || (videoFrame.Height != height))
{
return;
}
// check motion frame
if (motionFrame == null)
{
motionFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
// temporary buffer
if (suppressNoise)
{
tempFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
}
}
// convert current image to grayscale
Grayscale.CommonAlgorithms.BT709.Apply(videoFrame, motionFrame);
// pointers to background and current frames
byte *backFrame;
byte *currFrame;
int diff;
backFrame = (byte *)backgroundFrame.ImageData.ToPointer();
currFrame = (byte *)motionFrame.ImageData.ToPointer();
// 1 - get difference between frames
// 2 - threshold the difference
for (int i = 0; i < frameSize; i++, backFrame++, currFrame++)
{
// difference
diff = (int)*currFrame - (int)*backFrame;
// treshold
*currFrame = ((diff >= differenceThreshold) || (diff <= differenceThresholdNeg)) ? (byte)255 : (byte)0;
}
if (suppressNoise)
{
// suppress noise and calculate motion amount
UnmanagedMemoryHelper.CopyUnmanagedMemory(tempFrame.ImageData, motionFrame.ImageData, frameSize);
erosionFilter.Apply(tempFrame, motionFrame);
if (keepObjectEdges)
{
UnmanagedMemoryHelper.CopyUnmanagedMemory(tempFrame.ImageData, motionFrame.ImageData, frameSize);
dilatationFilter.Apply(tempFrame, motionFrame);
}
}
// calculate amount of motion pixels
pixelsChanged = 0;
byte *motion = (byte *)motionFrame.ImageData.ToPointer();
for (int i = 0; i < frameSize; i++, motion++)
{
pixelsChanged += (*motion & 1);
}
}
}
/// <summary>
/// Process new video frame.
/// </summary>
///
/// <param name="videoFrame">Video frame to process (detect motion in).</param>
///
/// <remarks><para>Processes new frame from video source and detects motion in it.</para>
///
/// <para>Check <see cref="MotionLevel"/> property to get information about amount of motion
/// (changes) in the processed frame.</para>
/// </remarks>
///
public unsafe void ProcessFrame(UnmanagedImage videoFrame)
{
lock (sync)
{
// check background frame
if (backgroundFrame == null)
{
lastTimeMeasurment = DateTime.Now;
// save image dimension
width = videoFrame.Width;
height = videoFrame.Height;
// alocate memory for previous and current frames
backgroundFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
motionFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
frameSize = motionFrame.Stride * height;
// temporary buffer
if (suppressNoise)
{
tempFrame = UnmanagedImage.Create(width, height, PixelFormat.Format8bppIndexed);
}
// convert source frame to grayscale
Grayscale.CommonAlgorithms.BT709.Apply(videoFrame, backgroundFrame);
return;
}
// check image dimension
if ((videoFrame.Width != width) || (videoFrame.Height != height))
{
return;
}
// convert current image to grayscale
Grayscale.CommonAlgorithms.BT709.Apply(videoFrame, motionFrame);
// pointers to background and current frames
byte *backFrame;
byte *currFrame;
int diff;
// update background frame
if (millisecondsPerBackgroundUpdate == 0)
{
// update background frame using frame counter as a base
if (++framesCounter == framesPerBackgroundUpdate)
{
framesCounter = 0;
backFrame = (byte *)backgroundFrame.ImageData.ToPointer();
currFrame = (byte *)motionFrame.ImageData.ToPointer();
for (int i = 0; i < frameSize; i++, backFrame++, currFrame++)
{
diff = *currFrame - *backFrame;
if (diff > 0)
{
(*backFrame)++;
}
else if (diff < 0)
{
(*backFrame)--;
}
}
}
}
else
{
// update background frame using timer as a base
// get current time and calculate difference
DateTime currentTime = DateTime.Now;
TimeSpan timeDff = currentTime - lastTimeMeasurment;
// save current time as the last measurment
lastTimeMeasurment = currentTime;
int millisonds = (int)timeDff.TotalMilliseconds + millisecondsLeftUnprocessed;
// save remainder so it could be taken into account in the future
millisecondsLeftUnprocessed = millisonds % millisecondsPerBackgroundUpdate;
// get amount for background update
int updateAmount = (int)(millisonds / millisecondsPerBackgroundUpdate);
backFrame = (byte *)backgroundFrame.ImageData.ToPointer();
currFrame = (byte *)motionFrame.ImageData.ToPointer();
for (int i = 0; i < frameSize; i++, backFrame++, currFrame++)
{
diff = *currFrame - *backFrame;
if (diff > 0)
{
(*backFrame) += (byte)((diff < updateAmount) ? diff : updateAmount);
}
else if (diff < 0)
{
(*backFrame) += (byte)((-diff < updateAmount) ? diff : -updateAmount);
}
}
}
backFrame = (byte *)backgroundFrame.ImageData.ToPointer();
currFrame = (byte *)motionFrame.ImageData.ToPointer();
// 1 - get difference between frames
// 2 - threshold the difference
for (int i = 0; i < frameSize; i++, backFrame++, currFrame++)
{
// difference
diff = (int)*currFrame - (int)*backFrame;
// treshold
*currFrame = ((diff >= differenceThreshold) || (diff <= differenceThresholdNeg)) ? (byte)255 : (byte)0;
}
if (suppressNoise)
{
// suppress noise and calculate motion amount
UnmanagedMemoryHelper.CopyUnmanagedMemory(tempFrame.ImageData, motionFrame.ImageData, frameSize);
erosionFilter.Apply(tempFrame, motionFrame);
if (keepObjectEdges)
{
UnmanagedMemoryHelper.CopyUnmanagedMemory(tempFrame.ImageData, motionFrame.ImageData, frameSize);
dilatationFilter.Apply(tempFrame, motionFrame);
}
}
// calculate amount of motion pixels
pixelsChanged = 0;
byte *motion = (byte *)motionFrame.ImageData.ToPointer();
for (int i = 0; i < frameSize; i++, motion++)
{
pixelsChanged += (*motion & 1);
}
}
}