/// <summary>
/// 图片灰度化和二值化
/// </summary>
private void ImageGray()
{
Dictionary <float, int> pixelCounts = new Dictionary <float, int>();
Texture2D tt = TextureTool.TextureToTexture2D(img.texture);
Texture2D grayTexture = new Texture2D(tt.width, tt.height);
for (int y = 0; y < tt.height; ++y)
{
for (int x = 0; x < tt.width; ++x)
{
Color curColor = tt.GetPixel(x, y);
float g = curColor.r * 0.299f + curColor.g * 0.587f + curColor.b * 0.114f;
//grayTexture.SetPixel(x, y, new Color(g, g, g, 1f));
// 记录相同灰度亮度值的像素有多少个
int lumina = (int)(g * 256);
if (pixelCounts.ContainsKey(lumina))
{
pixelCounts[lumina] = pixelCounts[lumina] + 1;
}
else
{
pixelCounts[lumina] = 1;
}
}
}
//grayTexture.Apply();
//img2.texture = grayTexture;
// 图像二值化与otsu算法,获取平均阈值
float[] s_max = new float[2] {
0, -10
};
for (int i = 0; i < 256; ++i)
{
int w_0 = 0, w_1 = 0, u_0 = 0, u_1 = 0, u = 0, g = 0;
foreach (KeyValuePair <float, int> val in pixelCounts)
{
if (val.Key < i)
{
w_0 += val.Value; // 得到阈值以下像素个数的和
}
else
{
w_1 += val.Value; // 得到阈值以上像素个数的和
}
}
// 得到阈值下所有像素的平均灰度
for (int b = 0; b < i; b++)
{
if (pixelCounts.ContainsKey(b))
{
u_0 += w_0 > 0 ? (b * pixelCounts[b]) / w_0 : 0;
}
}
for (int c = 200; c < 256; c++)
{
if (pixelCounts.ContainsKey(c))
{
u_1 += w_1 > 0 ? (c * pixelCounts[c]) / w_1 : 0;
}
}
// 总平均灰度
u = w_0 * u_0 + w_1 * u_1;
// 类间方差
g = w_0 * (u_0 - u) * (u_0 - u) + w_1 * (u_1 - u) * (u_1 - u);
// 类间方差等价公式
//g = w_0 * w_1 * (u_0 * u_1) * (u_0 * u_1);
// 取最大的
if (g > s_max[1])
{
s_max = new float[2] {
i, g
}
}
;
}
Debug.Log(s_max[0]);
// 二值化
for (int y = 0; y < tt.height; ++y)
{
for (int x = 0; x < tt.width; ++x)
{
Color curColor = tt.GetPixel(x, y);
float g = curColor.r * 0.299f + curColor.g * 0.587f + curColor.b * 0.114f;
Color newColor = curColor;
int lumina = (int)(g * 256);
if (lumina > s_max[0])
{
newColor = new Color(1, 1, 1, 0);
}
else
{
newColor = new Color(0, 0, 0, curColor.a);
}
grayTexture.SetPixel(x, y, newColor);
}
}
grayTexture.Apply();
img2.texture = grayTexture;
OnCreateMesh_4(grayTexture.width, grayTexture.height, grayTexture.GetPixels());
//OnCreateMesh_3(grayTexture);
}