下面是一个图片模糊处理的扩展方法，给予有需要用到的伙伴
建立一个imgView 的分类方便直接调用

.h

     /**
    *  对图片进行模糊
    *
     *  @param image 要处理图片
     *  @param blur  模糊系数 (0.0-1.0)
     *
     *  @return 处理后的图片
     */
    + (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur;
    @end

.m

 /**
 *  对图片进行模糊
 *
 *  @param image 要处理图片
 *  @param blur  模糊系数 (0.0-1.0)
 *
 *  @return 处理后的图片
 */
 + (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {
        if (!image) {
        return nil;
        }
    if ((blur < 0.0f) || (blur > 1.0f)) {
        blur = 0.5f;
    }
    
int boxSize = (int)(blur * 200);
boxSize -= (boxSize % 2) + 1;

CGImageRef img = image.CGImage;

vImage_Buffer inBuffer, outBuffer;
vImage_Error error;
void *pixelBuffer;

CGDataProviderRef inProvider = CGImageGetDataProvider(img);
CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);

inBuffer.width = CGImageGetWidth(img);
inBuffer.height = CGImageGetHeight(img);
inBuffer.rowBytes = CGImageGetBytesPerRow(img);
inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);

pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

outBuffer.data = pixelBuffer;
outBuffer.width = CGImageGetWidth(img);
outBuffer.height = CGImageGetHeight(img);
outBuffer.rowBytes = CGImageGetBytesPerRow(img);

error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL,
                                   0, 0, boxSize, boxSize, NULL,
                                   kvImageEdgeExtend);


if (error) {
    NSLog(@"error from convolution %ld", error);
}

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef ctx = CGBitmapContextCreate(
                                         outBuffer.data,
                                         outBuffer.width,
                                         outBuffer.height,
                                         8,
                                         outBuffer.rowBytes,
                                         colorSpace,
                                         CGImageGetBitmapInfo(image.CGImage));

CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

//clean up
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);

free(pixelBuffer);
CFRelease(inBitmapData);

CGColorSpaceRelease(colorSpace);
CGImageRelease(imageRef);

 return returnImage;
}