How to Implement the Sharpening Effect in the Image?
How To Implement The Sharpening Effect In The Image?¶
Introduction
If the image is too blurred. We can use the sharpening filter. There are a 3 by 3 matrix matching the image. We do the amount of the pixels of the 3 by 3 matrix. The result is the center pixel value of the 3 by 3 matrix. We will rewrite the result in the image. This is called convolution calculation.
Equipment
Operation System: Microsoft Windows 7 (64 bit)
Development Utility: Microsoft Visual Studio 2010
Usage
// The variable of the sharpening.
double dobAValue = 1.2;
// The sharpening of 3 by 3 matrix.
double adobS[3][3] = { { (0.0), -(dobAValue), (0.0) },
{-(dobAValue), (4 * dobAValue) + 1, -(dobAValue) },
{ (0.0), -(dobAValue), (0.0) } };
// The height of the image
for ( int iY = 1; iY < imageA->DibInfo->bmiHeader.biHeight - 1; iY++ )
{
// The width of the image
for ( int iX = 1; iX < imageA->DibInfo->bmiHeader.biWidth - 1; iX++ )
{
// The variable of the result.
dobFilterResult = 0;
// The height of the 3 by 3 matrix.
for ( intFWY = -1; intFWY <= 1; intFWY++ )
{
// The width of the 3 by 3 matrix.
for ( intFWX = -1; intFWX <= 1; intFWX++ )
{
// The index of the image with 3 by 3 matrix.
// The bit depth is three, so we multiplied by three.
lIDXA = ( (iX+intFWX) * 3 ) + ( (iY+intFWY) * imageA->DibInfo->bmiHeader.biWidth * 3 );
// The pixel of the blue channel.
byteRGB_BA = imageA->DibArry[lIDXA+0];
// The pixel of the green channel.
byteRGB_GA = imageA->DibArry[lIDXA+1];
// The pixel of the red channel.
byteRGB_RA = imageA->DibArry[lIDXA+2];
// Transform RGB color space to gray scale.
dobYUV_YA = (0.299 * byteRGB_RA + 0.587 * byteRGB_GA + 0.114 * byteRGB_BA);
// Convolution calculation.
dobFilterResult += ( adobS[intFWX+1][intFWY+1] * dobYUV_YA );
} // The closing "The width of the 3 by 3 matrix".
} // The closing "The height of the 3 by 3 matrix".
// Absolute value.
dobFilterResult = abs(dobFilterResult);
// The index of the image.
lIDXB = ( iX * 3 ) + ( iY * imageB->DibInfo->bmiHeader.biWidth * 3 );
// Set the pixel of the blue channel.
imageB->DibArry[lIDXB+0] = dobFilterResult;
// Set the pixel of the green channel.
imageB->DibArry[lIDXB+1] = dobFilterResult;
// Set the pixel of the red channel.
imageB->DibArry[lIDXB+2] = dobFilterResult;
} // The closing "The width of the image".
} // The closing "The height of the image".
You can download source code and binary code.
https://drive.google.com/file/d/0BzHb_OyLyVZlUER1QVdwcTBpTWc/view?usp=sharing
Exception
There is a notice, if your bit depth of bitmap file are not 24 bits, you should change your bitmap files to adapt this program, or you could rewrite this source code to fit your bitmap format.
You have to install Microsoft SDK v7.1, because I include windowscodes.lib.
#pragma comment(lib, "windowscodecs.lib")
Reference
[1] Gary Bradski and Adrian Kaehler, “Learning OpenCV: Computer Vision with the OpenCV Library,” O’REILLY, September 2008, ISBN:978-0-596-51613-0
Acknowledge
Thank you (Microsoft Visual Studio 2010, Lenna Sjööblom) very much for this great development utility and beautiful photo.
