cmsgamma.c

Linux下的无线网卡通用驱动程序

  c[2] = (-4 * lambda - d[1] * c[1] * e[1]) / d[2];
  e[2] = lambda / d[2];
  z[2] = w[2] * y[2] - c[1] * z[1];
  for (i = 3; i < m - 1; i++) {
    i1 = i - 1; i2 = i - 2;
    d[i]= w[i] + 6 * lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
    c[i] = (-4 * lambda -d[i1] * c[i1] * e[i1])/ d[i];
    e[i] = lambda / d[i];
    z[i] = w[i] * y[i] - c[i1] * z[i1] - e[i2] * z[i2];
  }
  i1 = m - 2; i2 = m - 3;
  d[m - 1] = w[m - 1] + 5 * lambda -c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
  c[m - 1] = (-2 * lambda - d[i1] * c[i1] * e[i1]) / d[m - 1];
  z[m - 1] = w[m - 1] * y[m - 1] - c[i1] * z[i1] - e[i2] * z[i2];
  i1 = m - 1; i2 = m - 2;
  d[m] = w[m] + lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
  z[m] = (w[m] * y[m] - c[i1] * z[i1] - e[i2] * z[i2]) / d[m];
  z[m - 1] = z[m - 1] / d[m - 1] - c[m - 1] * z[m];
  for (i = m - 2; 1<= i; i--)
     z[i] = z[i] / d[i] - c[i] * z[i + 1] - e[i] * z[i + 2];
}



// Smooths a curve sampled at regular intervals

BOOL LCMSEXPORT cmsSmoothGamma(LPGAMMATABLE Tab, double lambda)

{
    vec w, y, z;
    int i, nItems, Zeros, Poles;


    if (cmsIsLinear(Tab->GammaTable, Tab->nEntries)) return FALSE; // Nothing to do

    nItems = Tab -> nEntries;

    if (nItems > MAX_KNOTS) {
                cmsSignalError(LCMS_ERRC_ABORTED, "cmsSmoothGamma: too many points.");
                return FALSE;
                }

    ZeroMemory(w, nItems * sizeof(float));
    ZeroMemory(y, nItems * sizeof(float));
    ZeroMemory(z, nItems * sizeof(float));

    for (i=0; i < nItems; i++)
    {
        y[i+1] = (float) Tab -> GammaTable[i];
        w[i+1] = 1.0;
    }

    smooth2(w, y, z, (float) lambda, nItems);

    // Do some reality - checking...
    Zeros = Poles = 0;
    for (i=nItems; i > 1; --i) {

            if (z[i] == 0.) Zeros++;
            if (z[i] >= 65535.) Poles++;
            if (z[i] < z[i-1]) return FALSE; // Non-Monotonic
    }

    if (Zeros > (nItems / 3)) return FALSE;  // Degenerated, mostly zeros
    if (Poles > (nItems / 3)) return FALSE;  // Degenerated, mostly poles

    // Seems ok

    for (i=0; i < nItems; i++) {

        // Clamp to WORD

        float v = z[i+1];

        if (v < 0) v = 0;
        if (v > 65535.) v = 65535.;

        Tab -> GammaTable[i] = (WORD) floor(v + .5);
        }

    return TRUE;
}


// Check if curve is exponential, return gamma if so.

double LCMSEXPORT cmsEstimateGammaEx(LPWORD GammaTable, int nEntries, double Thereshold)
{
    double gamma, sum, sum2;
    double n, x, y, Std;
    int i;

    sum = sum2 = n = 0;
    
    // Does exclude endpoints   
    for (i=1; i < nEntries - 1; i++) {

            x = (double) i / (nEntries - 1);
            y = (double) GammaTable[i] / 65535.;
            
            // Avoid 7% on lower part to prevent 
            // artifacts due to linear ramps

            if (y > 0. && y < 1. && x > 0.07) {

            gamma = log(y) / log(x);
            sum  += gamma;
            sum2 += gamma * gamma;
            n++;
            }
            
    }

    // Take a look on SD to see if gamma isn't exponential at all
    Std = sqrt((n * sum2 - sum * sum) / (n*(n-1)));
    

    if (Std > Thereshold)
        return -1.0;

    return (sum / n);   // The mean
}


double LCMSEXPORT cmsEstimateGamma(LPGAMMATABLE t)
{
        return cmsEstimateGammaEx(t->GammaTable, t->nEntries, 0.7);
}


// -----------------------------------------------------------------Sampled curves

// Allocate a empty curve

LPSAMPLEDCURVE cmsAllocSampledCurve(int nItems)
{
    LPSAMPLEDCURVE pOut;

    pOut = (LPSAMPLEDCURVE) malloc(sizeof(SAMPLEDCURVE));
    if (pOut == NULL)
            return NULL;

    if((pOut->Values = (double *) malloc(nItems * sizeof(double))) == NULL)
    {
        free(pOut);
        return NULL;
    }

    pOut->nItems = nItems;
    ZeroMemory(pOut->Values, nItems * sizeof(double));

    return pOut;
}


void cmsFreeSampledCurve(LPSAMPLEDCURVE p)
{
    free((LPVOID) p -> Values);
    free((LPVOID) p);
}



// Does duplicate a sampled curve

LPSAMPLEDCURVE cmsDupSampledCurve(LPSAMPLEDCURVE p)
{
    LPSAMPLEDCURVE out;

    out = cmsAllocSampledCurve(p -> nItems);
    if (!out) return NULL;

    CopyMemory(out ->Values, p ->Values, p->nItems * sizeof(double));

    return out;
}


// Take min, max of curve

void cmsEndpointsOfSampledCurve(LPSAMPLEDCURVE p, double* Min, double* Max)
{
        int i;

        *Min = 65536.;
        *Max = 0.;

        for (i=0; i < p -> nItems; i++) {

                double v = p -> Values[i];

                if (v < *Min)
                        *Min = v;

                if (v > *Max)
                        *Max = v;
        }

        if (*Min < 0) *Min = 0;
        if (*Max > 65535.0) *Max = 65535.0;
}

// Clamps to Min, Max

void cmsClampSampledCurve(LPSAMPLEDCURVE p, double Min, double Max)
{

        int i;

        for (i=0; i < p -> nItems; i++) {

                double v = p -> Values[i];

                if (v < Min)
                        v = Min;

                if (v > Max)
                        v = Max;

                p -> Values[i] = v;

        }

}



// Smooths a curve sampled at regular intervals

BOOL cmsSmoothSampledCurve(LPSAMPLEDCURVE Tab, double lambda)
{
    vec w, y, z;
    int i, nItems;

    nItems = Tab -> nItems;

    if (nItems > MAX_KNOTS) {
                cmsSignalError(LCMS_ERRC_ABORTED, "cmsSmoothSampledCurve: too many points.");
                return FALSE;
                }

    ZeroMemory(w, nItems * sizeof(float));
    ZeroMemory(y, nItems * sizeof(float));
    ZeroMemory(z, nItems * sizeof(float));

    for (i=0; i < nItems; i++)
    {
        float value = (float) Tab -> Values[i];

        y[i+1] = value;
        w[i+1] = (float) ((value < 0.0) ?  0 : 1);
    }


    smooth2(w, y, z, (float) lambda, nItems);

    for (i=0; i < nItems; i++) {

        Tab -> Values[i] = z[i+1];;
     }

    return TRUE;

}


// Scale a value v, within domain Min .. Max 
// to a domain 0..(nPoints-1)

static
double ScaleVal(double v, double Min, double Max, int nPoints)
{

        double a, b;

        if (v <= Min) return 0;
        if (v >= Max) return (nPoints-1);
    
        a = (double) (nPoints - 1) / (Max - Min);
        b = a * Min;

        return (a * v) - b;

}


// Does rescale a sampled curve to fit in a 0..(nPoints-1) domain

void cmsRescaleSampledCurve(LPSAMPLEDCURVE p, double Min, double Max, int nPoints)
{

        int i;

        for (i=0; i < p -> nItems; i++) {

                double v = p -> Values[i];

                p -> Values[i] = ScaleVal(v, Min, Max, nPoints);
        }

}


// Joins two sampled curves for X and Y. Curves should be sorted.

LPSAMPLEDCURVE cmsJoinSampledCurves(LPSAMPLEDCURVE X, LPSAMPLEDCURVE Y, int nResultingPoints)
{
    int i, j;   
    LPSAMPLEDCURVE out;
    double MinX, MinY, MaxX, MaxY;
    double x, y, x1, y1, x2, y2, a, b;

    out = cmsAllocSampledCurve(nResultingPoints);
    if (out == NULL)
        return NULL;

    if (X -> nItems != Y -> nItems) {

        cmsSignalError(LCMS_ERRC_ABORTED, "cmsJoinSampledCurves: invalid curve.");
        cmsFreeSampledCurve(out);
        return NULL;
    }

    // Get endpoints of sampled curves
    cmsEndpointsOfSampledCurve(X, &MinX, &MaxX);
    cmsEndpointsOfSampledCurve(Y, &MinY, &MaxY);

    
    // Set our points
    out ->Values[0] = MinY; 
    for (i=1; i < nResultingPoints; i++) {

        // Scale t to x domain
        x = (i * (MaxX - MinX) / (nResultingPoints-1)) + MinX;

        // Find interval in which j is within (always up, 
        // since fn should be monotonic at all)

        j = 1;
        while ((j < X ->nItems - 1) && X ->Values[j] < x)
            j++;
            
        // Now x is within X[j-1], X[j]
        x1 = X ->Values[j-1]; x2 = X ->Values[j];
        y1 = Y ->Values[j-1]; y2 = Y ->Values[j];

        // Interpolate  the value
        a = (y1 - y2) / (x1 - x2);
        b = y1 - a * x1;
        y = a* x + b;
        
        out ->Values[i] = y;
    }
    

    cmsClampSampledCurve(out, MinY, MaxY);
    return out;
}



// Convert between curve types

LPGAMMATABLE cmsConvertSampledCurveToGamma(LPSAMPLEDCURVE Sampled, double Max)
{
    LPGAMMATABLE Gamma;
    int i, nPoints;
    

    nPoints = Sampled ->nItems;

    Gamma = cmsAllocGamma(nPoints);
    for (i=0; i < nPoints; i++) {
        
        Gamma->GammaTable[i] = (WORD) floor(ScaleVal(Sampled ->Values[i], 0, Max, 65536) + .5);
    }

    return Gamma;

}

// Inverse of anterior

LPSAMPLEDCURVE cmsConvertGammaToSampledCurve(LPGAMMATABLE Gamma, int nPoints)
{
    LPSAMPLEDCURVE Sampled;
    L16PARAMS L16;
    int i;
    WORD wQuant, wValIn;

    if (nPoints > 4096) {

        cmsSignalError(LCMS_ERRC_ABORTED, "cmsConvertGammaToSampledCurve: too many points (max=4096)");
        return NULL;
    }

    cmsCalcL16Params(Gamma -> nEntries, &L16);
       
    Sampled = cmsAllocSampledCurve(nPoints);
    for (i=0; i < nPoints; i++) {
            wQuant  = _cmsQuantizeVal(i, nPoints);
            wValIn  = cmsLinearInterpLUT16(wQuant, Gamma ->GammaTable, &L16);
            Sampled ->Values[i] = (float) wValIn;
    }

    return Sampled;
}




// Smooth endpoints (used in Black/White compensation)

BOOL _cmsSmoothEndpoints(LPWORD Table, int nEntries)
{
    vec w, y, z;
    int i, Zeros, Poles;

#ifdef DEBUG
        ASAVE(Table, nEntries, "nonsmt.txt");
#endif


    if (cmsIsLinear(Table, nEntries)) return FALSE; // Nothing to do

    
    if (nEntries > MAX_KNOTS) {
                cmsSignalError(LCMS_ERRC_ABORTED, "_cmsSmoothEndpoints: too many points.");
                return FALSE;
                }

    ZeroMemory(w, nEntries * sizeof(float));
    ZeroMemory(y, nEntries * sizeof(float));
    ZeroMemory(z, nEntries * sizeof(float));

    for (i=0; i < nEntries; i++)
    {
        y[i+1] = (float) Table[i];
        w[i+1] = 1.0;
    }

    w[1]        = 65535.0;
    w[nEntries] = 65535.0;

    smooth2(w, y, z, (float) nEntries, nEntries);

    // Do some reality - checking...
    Zeros = Poles = 0;
    for (i=nEntries; i > 1; --i) {

            if (z[i] == 0.) Zeros++;
            if (z[i] >= 65535.) Poles++;
            if (z[i] < z[i-1]) return FALSE; // Non-Monotonic
    }

    if (Zeros > (nEntries / 3)) return FALSE;  // Degenerated, mostly zeros
    if (Poles > (nEntries / 3)) return FALSE;    // Degenerated, mostly poles

    // Seems ok

    for (i=0; i < nEntries; i++) {

        // Clamp to WORD

        float v = z[i+1];

        if (v < 0) v = 0;
        if (v > 65535.) v = 65535.;

        Table[i] = (WORD) floor(v + .5);
        }

    return TRUE;
}