- (UIImage*) getBrighterImage:(UIImage *)originalImage
{
    UIImage *brighterImage;
    CIContext *context = [CIContext contextWithOptions:nil];
    CIImage *inputImage = [CIImage imageWithCGImage:originalImage.CGImage];

    CIFilter *lighten = [CIFilter filterWithName:@"CIColorControls"];
    [lighten setValue:inputImage forKey:kCIInputImageKey];
    [lighten setValue:@(0.3) forKey:@"inputBrightness"];
    
    CIImage *result = [lighten valueForKey:kCIOutputImageKey];
    CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];
    brighterImage = [UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);
    
    return brighterImage;
}

参考链接：

http://www.raywenderlich.com/22167/beginning-core-image-in-ios-6

http://blog.csdn.net/willyang519/article/details/38716019

iOS 图像处理－调整图像亮度