Question

我试图查看相机噪音。我也参考了http://www.cs.tut.fi/~foi/

但我想知道剪辑对于以下代码意味着什么。

：代码

%% ====================================================================================================================================
            %% 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

一般情况下，剪切是指当某个值超过某个阈值并被强制进入该阈值时会发生的情况。也称为饱和（当它是偶然的），夹紧（当故意）和其他。

这在数字系统中很常见，包括数字摄影，您可以使用具有指定位数的二进制值来表示某些数据。然后，该二进制值具有由位数和它们用于编码值的方式所暗示的上限和下限。

在此上下文中，代码似乎会生成要添加到图像的噪声。产生噪声的表达式没有被引用，但是注释表明泊松分布，这是一种数学函数，可以产生超过图像动态范围的输出。两个标志clipping_below和clipping_above是控制标志，允许用户指定是否应该剪切这些值，即约束到数据类型的上限和下限。

佳能或FinePix ISO图像的剪裁意味着什么？

1 个答案: