IOS--图像处理模板

IOS中提取图像的一般类是UIImage，其中图像原始数据的存储方式为RGBARGBARGBA(A-alpha)，进行一般的图像处理需要对其进行图像原始数据提取，具体代码为：

//功能：将IOS中的UIImage图像数据转换为rgbrgbrgb格式
//参数说明
//(UIImage*)image -- UIImage图像数据
//rgb_data :(unsigned char*)rgb_data -- 转换后的rgbrgb格式的图像数据


- (void)getRGBAsFromImage:(UIImage*)image rgb_data :(unsigned char*)rgb_data      //height * width * 3
{
    CGImageRef imageRef = [image CGImage];
    NSUInteger width = CGImageGetWidth(imageRef);
    NSUInteger height = CGImageGetHeight(imageRef);
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char));
    NSUInteger bytesPerPixel = 4;
    NSUInteger bytesPerRow = bytesPerPixel * width;
    NSUInteger bitsPerComponent = 8;
   CGContextRef context =  CGBitmapContextCreate(rawData, width, height,
                                                 bitsPerComponent, bytesPerRow, colorSpace,
                                                 kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);
    CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
    CGContextRelease(context);

    // Now your rawData contains the image data in the RGBA8888 pixel format.
    for (int i = 0 ; i < height * width; ++i)
    {
        rgb_data[i * 3 + 0] = rawData[i * 4 + 0]; //r
        rgb_data[i * 3 + 1] = rawData[i * 4 + 1]; //g
        rgb_data[i * 3 + 2] = rawData[i * 4 + 2]; //b
        //rawData[i * 4 + 3]; alpha
        
    }
    
    free(rawData);
}



//实例
- (void)viewDidLoad {
    [super viewDidLoad];
    UIImage *img = [UIImage imageNamed:@"1420268351640.jpg"];
    UIImageView *imgV= [[UIImageView alloc]initWithImage:img];
    unsigned char *rawData = (unsigned char*) calloc(imgWH * 3, sizeof(unsigned char));
    [self getRGBAsFromImage:img rgb_data:rawData];
    int vertex[8];
    int text_input[4];

    text_input[0] = 83;
    text_input[1] = 557;
    text_input[2] = 586;
    text_input[3] = 693;
    NSLog(@"imgH %f，imgW %f",imgV.frame.size.height,imgV.frame.size.width);
    card_detect_IO(rawData,imgV.frame.size.height , imgV.frame.size.width, text_input, vertex);

    
    int top_left_x, top_left_y, top_right_x, top_right_y, bottom_right_x, bottom_right_y, bottom_left_x, bottom_left_y;
    top_left_x = vertex[0];
    top_left_y = vertex[1];
    top_right_x = vertex[2];
    top_right_y = vertex[3];
    bottom_right_x = vertex[4];
    bottom_right_y = vertex[5];
    bottom_left_x = vertex[6];
    bottom_left_y = vertex[7];
    
    for(int i = 0 ; i<8 ;i++)
    {
        NSLog(@"%d  ",vertex [i]);
    }
    free(rawData);
} 

//功能：将unsigned char(rgbrgb）图像原始数据转换为UIImage格式
//参数说明：
//    输入参数： rawData rgb彩色图像原始数据（24位存储一个像素，rgbrgb存储格式）
//               height  rgb图像高度
//               width   rgb图像宽度
//    返回参数： UIImage*  返回UIIImage格式
- (UIImage*)imageFromRGB:(unsigned char*)rawData width:(int)width height:(int)height
{
    const size_t bufferLength = width * height * 3;
    NSData *data = [NSData dataWithBytes:rawData length:bufferLength];
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)data);
    
    // Creating CGImage from cv::Mat
    CGImageRef imageRef = CGImageCreate(width,          //width
                                        height,         //height
                                        8,              //bits per component
                                        24,             //bits per pixel
                                        width * 3,      //bytesPerRow
                                        colorSpace,     //colorspace
                                        kCGBitmapByteOrderDefault ,// bitmap info
                                        provider,               //CGDataProviderRef
                                        NULL,                   //decode
                                        false,                  //should interpolate
                                        kCGRenderingIntentDefault   //intent
                                        );
    
    // Getting UIImage from CGImage
    UIImage *finalImage = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef);
    CGDataProviderRelease(provider);
    CGColorSpaceRelease(colorSpace);
    
    return finalImage;
}