-(void) readImage:(UIImage*)inputImage
{
    CGImageRef inImage = [inputImage CGImage];
    //height of input image
    int ht = CGImageGetWidth(inImage);
    //width of input image
    int wdth = CGImageGetHeight(inImage);

    //determine colour space
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    //Array to store RGB values
    unsigned char *rawData = malloc(ht*wdth*4);
    //input image characteristics
    NSUInteger bytesPerRowImg = CGImageGetBytesPerRow(inImage);
    NSUInteger bitsPerComponentImg = CGImageGetBitsPerComponent(inImage);
    NSUInteger bitsPerPixelImg = CGImageGetBitsPerPixel(inImage);
   
    //create CGContext
 CGContextRefcontext=CGBitmapContextCreate(rawData,ht,wdth,bitsPerComponentImg,bytesPerRowImg,colorSpace,kCGImageAlphaPremultipliedLast| kCGBitmapByteOrder32Big);

    // One might change these parameters -
    // kCGImageAlphaPremultipliedLast| kCGBitmapByteOrder32Big
    // This depends upon RGBA/ ARGB (location of alpha)
    // and other parameters

    //free the colorspace
    CGColorSpaceRelease(colorSpace);
    CGContextDrawImage(context,CGRectMake(0,0,wdth,ht), inImage);
   
    //release CGImage
    CFRelease(inImage);

    //release context
    CGContextRelease(context);

    int byteIndex = 0;
   
    //Copy RGB values into rawData
    for(int i = 0;i < count; ++i)
    {
        Byte redColour = rawData[byteIndex];
        Byte greenColour = rawData[byteIndex+1];
        Byte blueColour = rawData[byteIndex+2];
        CGFloat alphaColour = rawData[byteIndex + 3]/255.0f;
        //would also depend upon CGBitmapInfo of the input image
       
        byteIndex +=4;
    }

    /*
        The array rawData now contains the RGB values
        You might use these values for you image processing
        projects.
        Make sure you free this after your work
    */

    ///
    // Your RGBA manipulation code goes here
    // To access the RGBA data at a particular pixel (xCor,yCor)
    // int redValueAtPixel = rawData[wdth*yCor+xCor];
    // int greenValueAtPixel = rawData[wdth*yCor+xCor+1];
    // int blueValueAtPixel = rawData[wdth*yCor+xCor+2];
    // float alphaAtPixel = rawData[wdth*yCor+xCor+3]x255.0f;
    ///

    free(rawData);
}