数码相机手册

数码相机手册

目录

1.数码相机实现展望 (2)

2.数码相机开发环境 (2)

3.系统框架 (3)

4.系统关键类设计 (3)

5.系统核心代码分析 (4)

5.1.实时显示图像 (4)

5.2.图像格式转换函数 (4)

5.3.主屏幕鼠标事件 (5)

5.4.相册列表显示 (6)

6.项目移植流程 (6)

7.课程安排 (8)

1.数码相机实现展望

由于良好的性能、低廉的价格和灵活方便的特性，USB 摄像头正被广泛的集成到嵌入式系统中，通过USB 摄像头Linux系统可以比较方便地得到实时图像，这对某些要求实时图象监控的嵌入式系统是一个很不错的选择。但是由于嵌入式硬件平台的多样性，要在嵌入式产品上使用USB摄像头，还需要做一些移植的工作。

2.数码相机开发环境

软件环境：Fedroa9 +QT4.6.3 +QTCreator2.3

硬件环境：mini2440+USB摄像头

3.系统框架

4.系统关键类设计

5.系统核心代码分析

5.1.实时显示图像

实时显示图像通过刷新paint事件来实现，具体代码如下：

void ProcessImage::paintEvent(QPaintEvent *)

{

rs = vd->get_frame((void **)&p,&len);

convert_yuv_to_rgb_buffer(p,pp,Image_w,Image_h);

frame->loadFromData((uchar *)pp,/*len*/Image_w * Image_h * 3 * sizeof(char));

label->setPixmap(QPixmap::fromImage(*frame,Qt::AutoColor));

// label->show();

rs = vd->unget_frame();

}

5.2.图像格式转换函数

由于摄像头采集到的是yuv格式的图像，必须要经过转换才能在屏幕上显示出来

主要用到的函数有下面几个

/*yuv格式转换为rgb格式*/

int ProcessImage::convert_yuv_to_rgb_buffer(unsigned char *yuv, unsigned char *rgb, unsigned int width, unsigned int height)

{

unsigned int in, out = 0;

unsigned int pixel_16;

unsigned char pixel_24[3];

unsigned int pixel32;

int y0, u, y1, v;

for(in = 0; in < width * height * 2; in += 4) {

pixel_16 =

yuv[in + 3] << 24 |

yuv[in + 2] << 16 |

yuv[in + 1] << 8 |

yuv[in + 0];

y0 = (pixel_16 & 0x000000ff);

u = (pixel_16 & 0x0000ff00) >> 8;

y1 = (pixel_16 & 0x00ff0000) >> 16;

v = (pixel_16 & 0xff000000) >> 24;

pixel32 = convert_yuv_to_rgb_pixel(y0, u, v);

pixel_24[0] = (pixel32 & 0x000000ff);

pixel_24[1] = (pixel32 & 0x0000ff00) >> 8;

pixel_24[2] = (pixel32 & 0x00ff0000) >> 16;

rgb[out++] = pixel_24[0];

rgb[out++] = pixel_24[1];

rgb[out++] = pixel_24[2];

pixel32 = convert_yuv_to_rgb_pixel(y1, u, v);

pixel_24[0] = (pixel32 & 0x000000ff);

pixel_24[1] = (pixel32 & 0x0000ff00) >> 8;

pixel_24[2] = (pixel32 & 0x00ff0000) >> 16;

rgb[out++] = pixel_24[0];

rgb[out++] = pixel_24[1];

rgb[out++] = pixel_24[2];

}

return 0;

}

int ProcessImage::convert_yuv_to_rgb_pixel(int y, int u, int v)

{

unsigned int pixel32 = 0;

unsigned char *pixel = (unsigned char *)&pixel32;

int r, g, b;

r = y + (1.370705 * (v-128));

g = y - (0.698001 * (v-128)) - (0.337633 * (u-128));

b = y + (1.732446 * (u-128));

if(r > 255) r = 255;

if(g > 255) g = 255;

if(b > 255) b = 255;

if(r < 0) r = 0;

if(g < 0) g = 0;

if(b < 0) b = 0;

pixel[0] = r * 220 / 256;

pixel[1] = g * 220 / 256;

pixel[2] = b * 220 / 256;

return pixel32;

}

5.3.主屏幕鼠标事件

主屏幕为显示实时图像的界面，单击主屏幕，出来三个按钮，“照相”、“浏览”、“退出”，并将三个按钮的背景设置为透明。通过重写鼠标按下的方法实现，代码如下：

void ProcessImage::mousePressEvent(QMouseEvent *ev)

{

//设置按钮窗口透明及大小

fns= new QWidget();

fns->setWindowFlags(Qt::FramelessWindowHint);

fns->setAttribute(Qt::WA_TranslucentBackground, true);

fns->setAutoFillBackground(true);

fns->setGeometry(20,115,200,200);

photo = new QPushButton( "photo",fns );

pho_list = new QPushButton( "view",fns );

pho_exit = new QPushButton( "exit",fns );

//设置三个按钮的布局管理器

QHBoxLayout *hLayout2 = new QHBoxLayout(fns);

hLayout2->addWidget(photo);

hLayout2->addWidget(pho_list);

hLayout2->addWidget(pho_exit);

connect( photo, SIGNAL( clicked() ), this, SLOT( on_photo_clicked() ) );

connect( pho_list, SIGNAL( clicked() ), this, SLOT( on_pho_list_clicked()) );

connect( pho_exit, SIGNAL( clicked() ), this, SLOT( on_pho_exit_clicked() ) );

fns->show();

}

5.4.相册列表显示

void ListImage::list_jpg(vector mv)

{

vector::iterator it;

lab = new QLabel();

vector mv1;

QDir dir(QDir::currentPath());

QStringList infolist = dir.entryList(QDir::NoDotAndDotDot | QDir::AllEntries);

for(int i=0; i

{

mv1.push_back(infolist.at(i));

}

jpglist = new QListWidget();

jpglist->resize(320,240);

connect(jpglist,SIGNAL(itemClicked(QListWidgetItem*)),this,SLOT(show_jpg(QListWidgetIte m *)));

for(it = mv1.begin();it!=mv1.end();it++)

{

if( strstr((*it).toStdString().c_str(),".jpg") != NULL)

{

printf("it=%s\n",(*it).toStdString().c_str());

jpgvect.push_back(*it);

jpglist->addItem(tr((*it).toStdString().c_str()));

}

}

jpglist->show();

}

6.项目移植流程

7.课程安排