// Applies simple sharpening to the row data to improve performance of the 1D Readers.
public override BitArray getBlackRow(int y, BitArray row)
{
LuminanceSource source = LuminanceSource;
int width = source.Width;
if (row == null || row.Size < width)
{
row = new BitArray(width);
}
else
{
row.clear();
}
initArrays(width);
sbyte[] localLuminances = source.getRow(y, luminances);
int[] localBuckets = buckets;
for (int x = 0; x < width; x++)
{
int pixel = localLuminances[x] & 0xff;
localBuckets[pixel >> LUMINANCE_SHIFT]++;
}
int blackPoint = estimateBlackPoint(localBuckets);
int left = localLuminances[0] & 0xff;
int center = localLuminances[1] & 0xff;
for (int x = 1; x < width - 1; x++)
{
int right = localLuminances[x + 1] & 0xff;
// A simple -1 4 -1 box filter with a weight of 2.
int luminance = ((center << 2) - left - right) >> 1;
if (luminance < blackPoint)
{
row.set_Renamed(x);
}
left = center;
center = right;
}
return(row);
}
// Calculates the final BitMatrix once for all requests. This could be called once from the
// constructor instead, but there are some advantages to doing it lazily, such as making
// profiling easier, and not doing heavy lifting when callers don't expect it.
private void binarizeEntireImage()
{
if (matrix == null)
{
LuminanceSource source = LuminanceSource;
if (source.Width >= MINIMUM_DIMENSION && source.Height >= MINIMUM_DIMENSION)
{
sbyte[] luminances = source.Matrix;
int width = source.Width;
int height = source.Height;
int subWidth = width >> 3;
int subHeight = height >> 3;
int[][] blackPoints = calculateBlackPoints(luminances, subWidth, subHeight, width);
matrix = new BitMatrix(width, height);
calculateThresholdForBlock(luminances, subWidth, subHeight, width, blackPoints, matrix);
}
else
{
// If the image is too small, fall back to the global histogram approach.
matrix = base.BlackMatrix;
}
}
}
public override Binarizer createBinarizer(LuminanceSource source)
{
return new HybridBinarizer(source);
}
public HybridBinarizer(LuminanceSource source):base(source)
{
}
public override Binarizer createBinarizer(LuminanceSource source)
{
return(new HybridBinarizer(source));
}
public HybridBinarizer(LuminanceSource source) : base(source)
{
}
public override Binarizer createBinarizer(LuminanceSource source)
{
return new GlobalHistogramBinarizer(source);
}
public GlobalHistogramBinarizer(LuminanceSource source):base(source)
{
}
public override Binarizer createBinarizer(LuminanceSource source)
{
return(new GlobalHistogramBinarizer(source));
}
public GlobalHistogramBinarizer(LuminanceSource source) : base(source)
{
}
public GlobalHistogramBinarizer(LuminanceSource source)
: base(source)
{
luminances = EMPTY;
buckets = new int[LUMINANCE_BUCKETS];
}
