用另一種顏色替換圖像中的某種顏色Matlab

Question

我有一個圖像，我用Matlab打開使用imshow，我想用新顏色（150）替換每個像素的顏色值（140,50,61） ，57,80）。如果有人可以請告知我如何做到這一點。

Answer 1

假設A是輸入的圖像數據，這可能是一個辦法 -

%// Initialize vectors for old and new pixels tuplets 
oldval = [140,50,61] 
newval = [150,57,80] 

%// Reshape the input array to a 2D array, so that each column would 
%// reprsent one pixel color information. 
B = reshape(permute(A,[3 1 2]),3,[]) 

%// Find out which columns match up with the oldval [3x1] values 
matches = all(bsxfun(@eq,B,oldval(:)),1) 
%// OR matches = matches = ismember(B',oldval(:)','rows') 

%// Replace all those columns with the replicated versions of oldval 
B(:,matches) = repmat(newval(:),1,sum(matches)) 

%// Reshape the 2D array back to the same size as input array 
out = reshape(permute(B,[3 2 1]),size(A)) 

---

採樣運行 -

>> A 
A(:,:,1) = 
    140 140 140 
    40 140 140 
A(:,:,2) = 
    50 20 50 
    50 50 50 
A(:,:,3) = 
    61 65 61 
    61 61 61 
>> out 
out(:,:,1) = 
    150 140 150 
    40 150 150 
out(:,:,2) = 
    57 20 57 
    50 57 57 
out(:,:,3) = 
    80 65 80 
    61 80 80 

Answer 2

bsxfun是我會解決它的辦法。但是，如果您不熟悉它，則可以從圖像中提取每個通道，爲每個通道使用三個邏輯模板，然後使用logical AND進行組合。做和會發現你的圖像中的像素，尋找特定的RGB三重。

因此，我們相應地設置每個通道的輸出並重構圖像以產生輸出。

因此，鑑於你的輸入圖像A，一個可以這樣做：

red = A(:,:,1); green = A(:,:,2); blue = A(:,:,3); 
mred = red == 140; mgreen = green == 50; mblue = blue == 61; 
final_mask = mred & mgreen & mblue; 
red(final_mask) = 150; green(final_mask) = 57; blue(final_mask) = 80; 
out = cat(3, red, green, blue);