学习图像处理知识---Emgu3.4 image类学习（四）

图片尺寸变法

1.降图片变成指定大小（3个重载函数）

PyrDown() 尺寸变小

PyrUp() 尺寸变大

public Image<TColor, TDepth> Resize(
	double scale,
	Inter interpolationType
)

public Image<TColor, TDepth> Resize(
	int width,
	int height,
	Inter interpolationType
)

public Image<TColor, TDepth> Resize(
	int width,
	int height,
	Inter interpolationType,
	bool preserveScale  //如为true,图像比列不变。
)

pictureBox2.Image = YUAN.Resize(500, 500, Emgu.CV.CvEnum.Inter.Linear, false).Bitmap; 

旋转图片（3个重载函数）

public Image<TColor, TDepth> Rotate(
	double angle,
	TColor background,
	bool crop   //false,不裁切 要缩小图片，默认为中心点旋转，角度为正为顺时针
)

public Image<TColor, TDepth> Rotate(
	double angle,  
	PointF center,
	Inter interpolationMethod,
	TColor background,
	bool crop
)

 Emgu.CV.Image<Bgr, Byte> YUAN = new Image<Bgr, byte>((Bitmap)pictureBox1.Image);
            pictureBox2.Image = YUAN.Rotate(20,new Bgr(Color.Red),false ).Bitmap;

pictureBox2.Image = YUAN.Rotate(20,new PointF(100,50), Emgu.CV.CvEnum.Inter.Linear, new Bgr(Color.Red), true).Bitmap;

图片仿射变换（首先要得到2*3变换矩阵Mat mapMatrix）

采用CvInvoke类

public static Mat GetAffineTransform(
	PointF[] src,   //找3个点 源图像
	PointF[] dest  //目标图像
)

public static void GetRotationMatrix2D(
	PointF center,
	double angle,
	double scale,
	IOutputArray mapMatrix
)

public Image<TColor, TDepth> WarpAffine(
	Mat mapMatrix,
	Inter interpolationType,
	Warp warpType,
	BorderType borderMode,
	TColor backgroundColor
)

public Image<TColor, TDepth> WarpAffine(
	Mat mapMatrix,
	int width,
	int height,
	Inter interpolationType,
	Warp warpType,
	BorderType borderMode,
	TColor backgroundColor
)

Emgu.CV.Image<Bgr, Byte> YUAN = new Image<Bgr, byte>((Bitmap)pictureBox1.Image);
            Mat af1 = new Mat();  //得到2*3变换矩阵Mat mapMatrix
            CvInvoke.GetRotationMatrix2D(new PointF(YUAN.Width / 2, YUAN.Height / 2), 20, 1, af1);
            pictureBox2.Image = YUAN.WarpAffine(af1,Emgu.CV.CvEnum.Inter.Linear,Emgu.CV.CvEnum.Warp.Default,Emgu.CV.CvEnum.BorderType.Default,new Bgr(Color.Blue)).Bitmap;