image - 组合面具

Question

我正在尝试获取一个图像，其中除了几个彩色对象之外的所有内容都变灰，如下所示：

我的原始图像是这样的（帽子的颜色与上面的示例略有不同）：

我尝试应用阈值过程然后对图像进行二值化，这给了我以下结果（掩码在左侧，乘法结果在右侧）：

现在我正在尝试结合所有这些面具。我应该使用if循环将它组合成一个图像还是有更好的方法？我尝试使用(&,&,&)，但它变成了黑色图像。

Answer 1

您的原始图像有 7 个不同的区域：5 个彩色提示、手和背景。那么问题就变成了，我们如何忽略墙壁和手，这恰好是两个最大的区域，只保留提示的颜色。

如果您的 MATLAB 许可证允许，我建议您使用Color Thresholder App ( colorThresholder)，它可以让您在图像中找到合适的颜色表示。试验一分钟，我可以说L*a*b*色彩空间允许区域/颜色之间的良好分离：

然后我们可以导出这个函数，得到以下结果：

function [BW,maskedRGBImage] = createMask(RGB)
%createMask  Threshold RGB image using auto-generated code from colorThresholder app.
%  [BW,MASKEDRGBIMAGE] = createMask(RGB) thresholds image RGB using
%  auto-generated code from the colorThresholder app. The colorspace and
%  range for each channel of the colorspace were set within the app. The
%  segmentation mask is returned in BW, and a composite of the mask and
%  original RGB images is returned in maskedRGBImage.

% Auto-generated by colorThresholder app on 25-Dec-2018
%------------------------------------------------------


% Convert RGB image to chosen color space
I = rgb2lab(RGB);

% Define thresholds for channel 1 based on histogram settings
channel1Min = 0.040;
channel1Max = 88.466;

% Define thresholds for channel 2 based on histogram settings
channel2Min = -4.428;
channel2Max = 26.417;

% Define thresholds for channel 3 based on histogram settings
channel3Min = -12.019;
channel3Max = 38.908;

% Create mask based on chosen histogram thresholds
sliderBW = (I(:,:,1) >= channel1Min ) & (I(:,:,1) <= channel1Max) & ...
  (I(:,:,2) >= channel2Min ) & (I(:,:,2) <= channel2Max) & ...
  (I(:,:,3) >= channel3Min ) & (I(:,:,3) <= channel3Max);
BW = sliderBW;

% Invert mask
BW = ~BW;

% Initialize output masked image based on input image.
maskedRGBImage = RGB;

% Set background pixels where BW is false to zero.
maskedRGBImage(repmat(~BW,[1 1 3])) = 0;

end

现在您有了遮罩，我们可以轻松地将原始图像转换为灰度，沿^第三维复制它，然后使用逻辑索引从原始图像中获取彩色像素：

function q53922067
img = imread("https://i.stack.imgur.com/39WNm.jpg");

% Image segmentation:
BW = repmat( createMask(img), 1, 1, 3 ); % Note that this is the function shown above

% Keeping the ROI colorful and the rest gray:
gImg = repmat( rgb2gray(img), 1, 1, 3 ); % This is done for easier assignment later
gImg(BW) = img(BW);

% Final result:
figure(); imshow(gImg);
end

产生：

Answer 2

要组合掩码，请使用|（逐元素逻辑 OR），而不是&（逻辑 AND）。

mask = mask1 | mask2 | mask3;