public void CvDct(ref Mat DST, Mat SRC, int N)
{
Mat dct, idct;
Mat dct2, dct3;
int width = SRC.Width;//N;
int height = SRC.Height;//N;
DST = SRC.Clone();
//DCT,IDCT用の行列作成(double)
dct = new Mat(height, width, MatType.CV_64FC1);
idct = new Mat(height, width, MatType.CV_64FC1);
dct2 = new Mat(height, width, MatType.CV_64FC1);
dct3 = new Mat(height, width, MatType.CV_64FC1);
var indexer_DST = new MatOfByte3(DST).GetIndexer();
var indexer_dct = new MatOfDouble3(dct).GetIndexer();
//行列dctに画像データをコピー
//double fcos;
for (int x = 0; x < width; x++)
for (int y = 0; y < height; y++)
{
Vec3d color = indexer_dct[y, x];
color.Item0= indexer_DST[y, x].Item0 / 256.0;
indexer_dct[y,x] = color;
}
//DCT…dctをコサイン変換してdct2を作成します
Cv2.Dct(dct, dct2, DctFlags.None);
//dct2をDenomで割りdct3を作成します
PerformDenom(ref dct3, dct2);
//IDCT…dct3を逆コサイン変換します
Cv2.Dct(dct3, idct, DctFlags.Inverse);
var indexer_idct = new MatOfDouble3(idct).GetIndexer();
//逆変換用画像にデータをコピー
for (int x = 0; x < width; x++)
for (int y = 0; y < height; y++)
{
Vec3b color = indexer_DST[y, x];
color.Item0= (byte)(indexer_idct[y,x].Item0 * 256.0);
indexer_DST[y,x]=color;
}
////正規化
//double min, max;
//min = 4000000000000;
//max = -4000000000000;
//double offset = 0.0;
////輝度値の最大と最小を取得
//DST.MinMaxIdx(out min, out max);
////for (int x = 0; x < width; x++)
//// for (int y = 0; y < height; y++)
//// {
//// double data = indexer_DST[y,x].Item0;
//// if (data < min) min = data;
//// if (data > max) max = data;
//// }
//for (int x = 0; x < width; x++)
// for (int y = 0; y < height; y++)
// {
// Vec3b color = indexer_DST[y, x];
// double data = indexer_DST[y, x].Item0;
// if (data < min + offset) data = min + offset;
// color.Item0 = (byte)( (((data / (max - min + offset))) * 255.0) - (((min + offset) / (max - min + offset)) * 255.0) );
// indexer_DST[y,x] = color;
// }
////DST = idct.Clone();
//行列メモリを開放します
dct.Dispose();
dct2.Dispose();
dct3.Dispose();
idct.Dispose();
indexer_dct = null;
indexer_DST = null;
indexer_idct = null;
}
private void PerformDenom(ref Mat DST, Mat SRC)
{
double PI = 3.1416;
int width = SRC.Width;
int height = SRC.Height;
//XとYを準備
double[,] meshX = new double[height,width];
double[,] meshY = new double[height,width];
double[,] denom = new double[height,width];
DST = SRC.Clone();
var indexer = new MatOfDouble3(DST).GetIndexer();
//メッシュグリッドの作成
for (int y = 0; y < height; y++)
for (int x = 0; x < width; x++)
{
meshX[y, x] = x;
meshY[y, x] = y;
}
//固有値計算
for (int y = 0; y < height; y++)
for (int x = 0;x < width; x++)
denom[y, x] = (2.0 * Math.Cos(PI * (double)x / ((double)width)) - 2.0) + (2.0 * Math.Cos(PI * (double)y / ((double)height)) - 2.0);
//計算
for (int x = 0; x < width; x++)
for (int y = 0; y < height; y++)
{
//data_d[j][i] = data_s[j][i] / denom[j][i];
Vec3d color = indexer[y, x];
color.Item0 = indexer[y, x].Item0;
//ゼロ割防止
if (!(x == 0 && y == 0)) color.Item0 = color.Item0 / denom[y, x];
indexer[y, x] = color;
}
indexer = null;
}
