142 lines
3.5 KiB
Plaintext
142 lines
3.5 KiB
Plaintext
#include "Binarization.h"
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CBinarization::CBinarization( QString imgPath )
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: threshold(0)
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{
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// 加载图片
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_img = new QImage();
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if (NULL != _img)
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{
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_img->load(imgPath);
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}
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}
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// 生成灰度图像
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QImage* CBinarization::grayScaleImg()
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{
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if (NULL == _img)
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{
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return NULL;
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}
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int nWidth = _img->width();
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int nHeight = _img->height();
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// 这里留意，我使用了QImage::Format_Grayscale8格式的图片，这种图片每个像素只用了8bit存储灰度颜色值
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QImage* grayImg = new QImage(nWidth, nHeight, QImage::Format_RGB888);
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QRgb rgbVal = 0;
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int grayVal = 0;
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for (int x = 0; x < nWidth; ++x)
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{
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for (int y = 0; y < nHeight; ++y)
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{
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rgbVal = _img->pixel(x, y);
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grayVal = qGray(rgbVal); // 这里调用Qt的函数，使用(R * 11 + G * 16 + B * 5)/32的方法计算
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grayImg->setPixel(x, y, QColor(grayVal, grayVal, grayVal).rgb());
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}
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}
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return grayImg;
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}
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int CBinarization::Otsu(QImage* img)
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{
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if (NULL == img)
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{
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return -1;
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}
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vector<int> histogram = Histogram(img);
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int total = 0;
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for (int i = 0; i != histogram.size(); ++i)
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{
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total += histogram[i];
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}
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double sum = 0.0;
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for (unsigned int i = 1; i < histogram.size(); ++i)
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sum += i * histogram[i];
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double sumB = 0.0;
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double wB = 0.0;
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double wF = 0.0;
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double mB = 0.0;
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double mF = 0.0;
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double max = 0.0;
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double between = 0.0;
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double threshold = 0.0;
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for (int i = 0; i != 256; ++i)
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{
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wB += histogram[i];
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if (wB == 0)
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continue;
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wF = total - wB;
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if (wF == 0)
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break;
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sumB += i * histogram[i];
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mB = sumB / wB;
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mF = (sum - sumB) / wF;
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between = wB * wF * (mB - mF) * (mB - mF);
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if ( between > max )
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{
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threshold = i;
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max = between;
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}
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}
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return threshold;
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}
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QImage* CBinarization::process(QImage* img)
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{
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if (NULL == img)
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{
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return NULL;
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}
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int width = img->width();
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int height = img->height();
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int bytePerLine = img->bytesPerLine(); // 每一行的字节数
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unsigned char *data = img->bits();
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unsigned char *binarydata = new unsigned char[bytePerLine * height];
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unsigned char g = 0;
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for (int i = 0; i < height; ++i)
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{
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for (int j = 0; j < width; ++j)
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{
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g = *(data + i * bytePerLine + j * 3); // 这里j 乘以 3
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if(int(g) >= threshold)
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{
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binarydata[ i * bytePerLine + j * 3] = 0xFF; // 每个色值需要对3个字节赋值
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binarydata[ i * bytePerLine + j * 3 + 1] = 0xFF;
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binarydata[ i * bytePerLine + j * 3 + 2] = 0xFF;
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}
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else
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{
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binarydata[ i * bytePerLine + j * 3] = 0x00;
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binarydata[ i * bytePerLine + j * 3 + 1] = 0x00;
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binarydata[ i * bytePerLine + j * 3 + 2] = 0x00;
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}
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}
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}
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QImage *ret = new QImage(binarydata, width, height, bytePerLine, QImage::Format_RGB888);
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return ret;
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}
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std::vector<int> CBinarization::Histogram( QImage* img )
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{
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unsigned char* graydata = img->bits();
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vector<int> hist(256); // 256色
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for (int i = 0; i != img->width(); ++i)
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{
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for (int j = 0; j != img->height(); ++j)
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{
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int index = int(*graydata);
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hist[index] += 1;
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graydata += 1; // step
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}
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}
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graydata = NULL;
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return hist;
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}
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