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我正在编写一个使用双三次插值的程序，并且我正在使用 EasyBMP，但我遇到了问题。而输入图像是辣椒。

我的输出看起来像这样。

#define BOUNDS(val, min, max) if (val < min) { val = min; } else if (val > max) { val = max; }

void resize(float value)
{
    BMP* temp = new BMP();
    int in_w = image->TellWidth();
    int in_h = image->TellHeight();
    temp->SetSize(in_w*value, in_h*value);
    RGBApixel input;

    for (int y = 0; y < temp->TellHeight(); ++y)
    {
        float v = float(y) / float(temp->TellHeight() - 1);
        for (int x = 0; x < temp->TellWidth(); ++x)
        {
            float u = float(x) / float(temp->TellWidth() - 1);

            input = this->bicubicInterpolation(u,v);

            temp->SetPixel(x,y,input);
        }
    }

    delete image;
    image=temp;
}


RGBApixel bicubicInterpolation(float u, float v)
{
    RGBApixel p[4][4];
    int q,w;

    float x = (u * image->TellWidth()) - 0.5;
    int xint = int(x);
    float dx = x - floor(x);

    float y = (v * image->TellHeight()) - 0.5;
    int yint = int(y);
    float dy = y - floor(y);

    for(int i=0; i<4; i++)
    {
        for(int j=0; j<4; j++)
        {
            q=xint - 1 + j;
            BOUNDS(q,0,image->TellWidth()-1)
            w=yint - 1 + i;
            BOUNDS(w,0,image->TellHeight()-1)
            p[j][i] = image->GetPixel(q,w);
        }
    }
    RGBApixel toReturn;
    RGBApixel el1 = this->interpolation(p[0][0],p[1][0], p[2][0], p[3][0], dx);
    RGBApixel el2 = this->interpolation(p[0][1],p[1][1], p[2][1], p[3][1], dx);
    RGBApixel el3 = this->interpolation(p[0][2],p[1][2], p[2][2], p[3][2], dx);
    RGBApixel el4 = this->interpolation(p[0][3],p[1][3], p[2][3], p[3][3], dx);
    RGBApixel value = this->interpolation(el1, el2, el3, el4, dy);

    return value;
}

RGBApixel interpolation(RGBApixel A, RGBApixel B, RGBApixel C, RGBApixel D, float t)
{
    float a[3],b[3],c[3],d[3];
    RGBApixel toRet;
    a[0]=A.Red;
    b[0]=B.Red;
    c[0]=C.Red;
    d[0]=D.Red;

    a[1]=A.Green;
    b[1]=B.Green;
    c[1]=C.Green;
    d[1]=D.Green;

    a[2]=A.Blue;
    b[2]=B.Blue;
    c[2]=C.Blue;
    d[2]=D.Blue;

    float w[3];
    float x[3];
    float y[3];
    float z[3];

    float color[3];

    for(int i=0; i<3; i++)
    {
        w[i]= -a[i] / 2.0f + (3.0f*b[i]) / 2.0f - (3.0f*c[i]) / 2.0f + d[i] / 2.0f;
        x[i]= a[i] - (5.0f*b[i]) / 2.0f + 2.0f*c[i] - d[i] / 2.0f;
        y[i]= -a[i] / 2.0f + c[i] / 2.0f;
        z[i]= b[i];
        color[i]= w[i] * t*t*t + x[i] * t*t + y[i] * t +z[i];
    }
    toRet.Red=color[0];
    toRet.Green=color[1];
    toRet.Blue=color[2];
    toRet.Alpha=255;

    return toRet;
}

你注意到我犯的错误了吗？

4

1 回答 1

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它超出了范围。只需要：

color[i]= w[i] * t*t*t + x[i] * t*t + y[i] * t +z[i];
BOUNDS(color[i],0,255);
于 2017-04-17T12:18:37.730 回答