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利用Qt绘图随机生成带多种干扰信息的数字图片

news 来源：原创 2025/5/24 6:17:32

背景

在学习AutoML或ML的过程中，需要一些图片类型的数据做分类预测训练，于是想到尝试最简单的数字识别，且单个数字的识别，也就是y的取值只有10种可能，即0到9。

以下参考代码分别考虑了数字字体的大小、数字颜色的深浅、线条的粗细、数字的倾斜、字体随机、图片背景色（纯色）的深浅、噪声点的位置和大小等要素，且进行随机生成。

代码

#include <QGuiApplication>
#include <QtCore>
#include <QtGui>
#include <QTransform>bool createImage(int number, int size, int sn)
{qsrand(QTime::currentTime().msec() * sn * qrand());QImage img = QImage(size, size, QImage::Format_RGB32);QPainter painter(&img);//白色到灰色[0.4~1.0]double lightness = qAbs(qrand()) % 500/1000.0 + 0.4;double v = 255 * lightness;painter.setBrush(QBrush(QColor(v, v, v)));painter.drawRect(0, 0, size, size);//亮色字体int t = qAbs(qrand());int r = (100 + t/150) % 150;int g = (100 + t%150) % 150;QPen pen(QColor(r, g, 0));pen.setWidthF(qAbs(qrand() % 4)); //线宽painter.setPen(pen);//旋转QTransform ransform;ransform.rotate(qrand() % 30* (qrand() % 3 - 1));painter.setTransform(ransform);//中心点随机int randSize = 20 * size / 100;QRectF textRect(QPointF(qAbs(qrand()) % randSize, qAbs(qrand()) % randSize),QSizeF(size-randSize, size-randSize));QString sNumber = QString::number(number);int fontSize = (30 + qrand() % 20) * size / 100;painter.setFont(QFont(qrand()%2 ? "SimSun" : "msyhbd", fontSize));painter.setRenderHint(QPainter::TextAntialiasing); //抗锯齿painter.drawText(textRect, Qt::AlignCenter, sNumber);//噪声点painter.setRenderHint(QPainter::HighQualityAntialiasing); //抗锯齿for (int i = 0; i < 5 + qrand() % 10; ++i){pen.setColor(QColor(qAbs(qrand())%255, qAbs(qrand())%255, qAbs(qrand())%255));pen.setWidth(2 + qrand() % 4);painter.setPen(pen);painter.drawPoint(qAbs(qrand())%size, qAbs(qrand())%size);}QString fileName = QString("num_%1_%2.png").arg(sn, 6, 10, QChar('0')).arg(sNumber);bool ok = img.save(fileName + ".tmp", "PNG", 0);if (ok){QFile::remove(fileName);ok = QFile::rename(fileName + ".tmp", fileName);}qDebug() << fileName << "Created!";return ok;
}int main(int argc, char *argv[])
{QGuiApplication a(argc, argv);for (int i = 0; i < 100000; ++i){createImage(qAbs(qrand())%10, 100, i);qDebug() << "Finish" << i;}return 0;
}