Canon或FinePix ISO圖像的裁剪是什麼意思？

Question

我正在嘗試查看相機噪音。 我也參考如下http://www.cs.tut.fi/~foi/

但我想知道在下面的代碼中剪切的含義是什麼。

：代碼

%% ==================================================================================================================================== 
      %% LOAD BITMAP/RAW IMAGE % raw-data images which are loaded below can be downloaded from http://www.cs.tut.fi/~foi/sensornoise.html 
      %% ==================================================================================================================================== 
      if 1 %% load "noise-free" image and add noise (OTHERWISE LOAD RAW DATA, SEE BELOW) 
       add_noise=1;    % add noise to image 
       a=0.1^2; b=0.04^2;  % noise parameters a,b 
       % a=0.1^2; b=0.02^2;  % noise parameters a,b 
       % a=0.0^2; b=0.2^2;  % noise parameters a,b 
       % a=(1/30); b=0.1^2;  % noise parameters a,b 

       clipping_below=1; % on/off [keep off for pure-poissonian (no gaussian terms) noise, since there are no negative errors] 
       clipping_above=1; % on/off 
       prior_density=1;     % type of prior density to use for ML (0) 
       %        % 1: zero_one uniform prior density [0,1]; 


       %  y=im2double(imread('image_man1024.tiff')); 
       %  y=im2double(imread('image_testpat1024.tiff')); 
       y=im2double(imread('y_piecewise.tif')); 
       %  y=im2double(imread('y_piecewise_fibo.tif')); 

      else %% RAW %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
       add_noise=0; %% DO NOT ADD NOISE TO RAW-DATA (IT HAS ENOUGH NOISE ALREADY! :)) 
       clipping_below=1; %%%% on off %% RAW-DATA IS ASSUMED TO BE CLIPPED FROM ABOVE AND BELOW 
       clipping_above=1; %%%% on off 
       prior_density=0;     % type of prior density to use for ML (0) 
       %        % 0: zero_infty uniform prior density (R+); (default, use this for raw-data) 

Answer 1

裁剪一般是當值超過某個閾值，並強迫該閾值時會發生什麼。也稱爲飽和（意外時），夾緊（故意）等。

在包括數字攝影在內的數字系統中，您使用具有指定位數的二進制值來表示某些數據時很常見。然後該二進制值具有由位數和它們用於編碼值的方式所暗示的上限和下限。

在這種情況下，它看起來像代碼產生噪聲添加到圖像。生成噪聲的表達式未被引用，但評論提示了泊松分佈，這是一種數學函數，可以產生超過圖像動態範圍的輸出。兩個標誌clipping_below和clipping_above是控制標誌，它們允許用戶指定是否應該限制這些值，即限制到數據類型的上限和下限。