优化Niblack＆＃39; Niblack＆＃39;在MATLAB中进行阈值处理？

Question

我已经在MATLAB（R2014B）的图像上实现了Niblack阈值处理：

function [ ] = processing_local( )

    x = imread('HW8.png');

%   Resize the image.  
    size(x);
    x = imresize(x,[500 800]);

    figure;
    imshow(x);
    title('Original');

    x = imadjust(x, [0.2,0.8],[0.5,1.0]);

%   HSV plane, extracting the value part.
    z = rgb2hsv(x);       
    v = z(:,:,3);
    v = imadjust(v);

%   Finding the mean and standard deviation.  
    m = mean(v(:));
    s = std(v(:));
    k = -.4;
    value = m+ k*s;
    temp = v;

%   Niblack  
    for p = 1:1:500
        for q = 1:1:800
            pixel = temp(p,q);
                if(pixel > value)
                    temp(p,q)= 1;
                else
                    temp(p,q)= 0;
                end
         end
    end

    figure;
    imshow(temp);
    title('Niblack Result.');

    end

我看到的结果是：

Output of Niblack thresholding

如图所示，图像有很多黑点被降级，我将如何在MATLAB中对其进行优化？

我想尝试一些统一的亮度，但不能在函数内实现。我在一个单独的函数中写了它：

function [ ] = practice_white( )

        x = imread('HW4.png');
        x = rgb2gray(x);

        background = imopen(x,strel('disk',15));

        white = imclose(x, background);
        whiteAdjusted = x ./ (white)*0.85;

        BW = imbinarize(whiteAdjusted, 0.2);

        figure
        imshow(BW); title('Test');

    end