如何读取10位原始图像?其中包含RGB-IR数据

时间:2016-09-21 17:30:17

标签: python matlab numpy image-processing

我想知道如何从我的10位原始数据(它有rgb-ir imagedata)数据中提取rgb图像?

如何阅读Python或MATLAB?

拍摄时的相机分辨率为1280x720: 室内照片Image for download 户外照片Image 2 for download

相机型号:e-CAM40_CUMI4682_MOD

非常感谢

1 个答案:

答案 0 :(得分:7)

我使用了以下图像处理阶段:

  • 拜耳马赛克彩色通道分离。
  • 线性拉伸每个颜色通道。
  • 简单的白平衡。
  • 用绿色替换IR颜色通道(将图像转换为标准拜耳格式)。
  • 恢复拜耳马赛克。
  • 简单的伽马校正。
  • 去马赛克

我没有处理IR颜色通道,而是将其替换为绿色通道。

根据您添加的RGB图像,我找到了CFA订单 CFA(滤色器阵列)顺序为:

B | G
-- --
IR| R

以下Matlab代码将图像处理为RGB:

srcN = 1280;
srcM = 720;

f = fopen('image_raw.raw', 'r');

%Read as transposed matrix dimensions, and transpose the matrix.
%The reason for that, is that Matlab memory oreder is column major, and
%raw image is stored in row major (like C arrays).
I = fread(f, [srcN, srcM], 'uint16');
fclose(f);
I = I';

%Convert from range [0, 1023] range [0, 1] (working in double image format).
I = I/(2^10-1);

%Bayer mosaic color channel separation
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Assume input format is GBRG Bayer mosaic format.
%Separate to color components.
B = I(1:2:end, 1:2:end);
G = I(1:2:end, 2:2:end);
IR = I(2:2:end, 1:2:end);
R = I(2:2:end, 2:2:end);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Linear stretching each color channel.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Linear streatch blue color channel.
B = imadjust(B, stretchlim(B, [0.02 0.98]),[]);

%Linear streatch green channel.
G = imadjust(G, stretchlim(G, [0.02 0.98]),[]);

%Linear streatch red color channel.
R = imadjust(R, stretchlim(R, [0.02 0.98]),[]);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Simple white balance
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Median or R, G and B.
rgb_med = [median(R(:)), median(G(:)), median(B(:))];
rgb_scale = max(rgb_med)./rgb_med;

%Scale each color channel, to have the same median.
R = R*rgb_scale(1);
G = G*rgb_scale(2);
B = B*rgb_scale(3);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Restore Bayer mosaic.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Insert streached color channnels back into I.
I(1:2:end, 1:2:end) = B;
I(1:2:end, 2:2:end) = G;
%I(2:2:end, 1:2:end) = G; %Replace IR with Green.
I(2:2:end, 2:2:end) = R;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Replace IR with green - resize green to full size of image first.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
T = imresize(G, [srcM, srcN]); %T - temporary green, size 1280x720
I(2:2:end, 1:2:end) = T(2:2:end, 1:2:end); %Replace IR with Green.
I = max(min(I, 1), 0); %Limit I to range [0, 1].
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Simple gamma correction
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gamma = 0.45;
I = I.^gamma;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Demosaic
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Convert to uint8 (range [0, 255]).
I = uint8(round(I*255));
RGB = demosaic(I, 'bggr');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

imshow(RGB);

结果:

enter image description here

现在颜色正常......

户外图像处理:

应用"室内"处理室外图像,得到以下结果:

enter image description here

白树是近红外光谱穿透R,G和B像素(不仅是红外像素)的标志。
植被的叶绿素在近红外光谱中具有高反射。请参阅:http://missionscience.nasa.gov/ems/08_nearinfraredwaves.html‌​,然后在Google上进行搜索 需要从红色,绿色和蓝色通道中减去IR。

我使用了以下图像处理阶段:

  • 拜耳马赛克彩色通道分离。
  • 减去IR"盈余"来自红色,绿色和蓝色通道。
  • 线性拉伸每个颜色通道。
  • 简单的白平衡。
  • 恢复拜耳马赛克。
  • 简单的伽马校正。
  • 去马赛克。
  • 将RGB图像调整为较低分辨率。

以下Matlab代码将室外图像处理为RGB:

srcN = 1280;
srcM = 720;

f = fopen('ir_6.raw', 'r');

%Read as transposed matrix dimensions, and transpose the matrix.
%The reason for that, is that Matlab memory oreder is column major, and
%raw image is stored in row major (like C arrays).
I = fread(f, [srcN, srcM], 'uint16');
fclose(f);
I = I';

%Convert from range [0, 1023] range [0, 1] (working in double image format).
I = I/(2^10-1);

%Bayer mosaic color channel separation
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Assume input format is GBRG Bayer mosaic format.
%Separate to color components.
B = I(1:2:end, 1:2:end);
G = I(1:2:end, 2:2:end);
IR = I(2:2:end, 1:2:end);
R = I(2:2:end, 2:2:end);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Subtract IR "surplus" from R, G and B.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%The coefficients were tuned by trial and error...
ir_r = 1.3;  % 130% of IR radiation is absorbed by red pixels??? 
ir_g = 0.35; % 35% of IR radiation is absorbed by green pixels.
ir_b = 0.3;  % 30% of IR radiation is absorbed by blue pixels.

IR = imresize(IR, size(I)); %Resize IR to the size of I.
IR = max(min(IR, 1), 0); %Limit IR to range [0, 1] (because imresize values slightly outside the range of input).

R = R - IR(2:2:end, 2:2:end)*ir_r; %Subtract IR for R (IR scale coefficient is ir_r).
G = G - IR(1:2:end, 2:2:end)*ir_g; %Subtract IR for G (IR scale coefficient is ir_g).
B = B - IR(1:2:end, 1:2:end)*ir_b; %Subtract IR for B (IR scale coefficient is ir_b).

R = max(min(R, 1), 0); %Limit IR to range [0, 1] 
G = max(min(G, 1), 0);
B = max(min(B, 1), 0);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Linear stretching each color channel.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Linear streatch blue color channel.
B = imadjust(B, stretchlim(B, [0.02 0.98]),[]);

%Linear streatch green channel.
G = imadjust(G, stretchlim(G, [0.02 0.98]),[]);

%Linear streatch red color channel.
R = imadjust(R, stretchlim(R, [0.02 0.98]),[]);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Simple white balance
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Median or R, G and B.
rgb_med = [median(R(:)), median(G(:)), median(B(:))];
rgb_scale = max(rgb_med)./rgb_med;

%Scale each color channel, to have the same median.
R = R*rgb_scale(1);
G = G*rgb_scale(2);
B = B*rgb_scale(3);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Restore Bayer mosaic.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Insert streached color channnels back into I.
I(1:2:end, 1:2:end) = B;
I(1:2:end, 2:2:end) = G;
I(2:2:end, 2:2:end) = R;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Replace IR with green - resize green to full size of image first.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
T = imresize(G, [srcM, srcN]); %T - temporary green, size 1280x720
I(2:2:end, 1:2:end) = T(2:2:end, 1:2:end); %Replace IR with Green.
I = max(min(I, 1), 0); %Limit I to range [0, 1].
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Simple gamma correction
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gamma = 0.45;
I = I.^gamma;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Demosaic
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Convert to uint8 (range [0, 255]).
I = uint8(round(I*255));
RGB = demosaic(I, 'bggr');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

RGB = imresize(RGB, size(I)/2); %Shrink size of RGB image for reducing demosaic artifacts.

imshow(RGB);

结果并不是那么好,但它展示了可以从红绿蓝通道中减去红外通道的概念。
仍有工作要做......
结果图片:

enter image description here

"假色的原因"绿色补丁:
红色通道中的饱和像素(原始输入中饱和)未得到妥善处理 可以通过减少曝光来解决问题(以较低的曝光时间拍摄)。