将jet图像改为灰度图

jet是一个256位颜色索引，用matlab可以把灰度图变成jet图片，但是怎么反过来我在matlab上没找到，所以只好自己另写程序了。

以下是jet.txt，是jet的颜色索引。

0.000000 0.000000 0.5156250.000000 0.000000 0.5312500.000000 0.000000 0.5468750.000000 0.000000 0.5625000.000000 0.000000 0.5781250.000000 0.000000 0.5937500.000000 0.000000 0.6093750.000000 0.000000 0.6250000.000000 0.000000 0.6406250.000000 0.000000 0.6562500.000000 0.000000 0.6718750.000000 0.000000 0.6875000.000000 0.000000 0.7031250.000000 0.000000 0.7187500.000000 0.000000 0.7343750.000000 0.000000 0.7500000.000000 0.000000 0.7656250.000000 0.000000 0.7812500.000000 0.000000 0.7968750.000000 0.000000 0.8125000.000000 0.000000 0.8281250.000000 0.000000 0.8437500.000000 0.000000 0.8593750.000000 0.000000 0.8750000.000000 0.000000 0.8906250.000000 0.000000 0.9062500.000000 0.000000 0.9218750.000000 0.000000 0.9375000.000000 0.000000 0.9531250.000000 0.000000 0.9687500.000000 0.000000 0.9843750.000000 0.000000 1.0000000.000000 0.015625 1.0000000.000000 0.031250 1.0000000.000000 0.046875 1.0000000.000000 0.062500 1.0000000.000000 0.078125 1.0000000.000000 0.093750 1.0000000.000000 0.109375 1.0000000.000000 0.125000 1.0000000.000000 0.140625 1.0000000.000000 0.156250 1.0000000.000000 0.171875 1.0000000.000000 0.187500 1.0000000.000000 0.203125 1.0000000.000000 0.218750 1.0000000.000000 0.234375 1.0000000.000000 0.250000 1.0000000.000000 0.265625 1.0000000.000000 0.281250 1.0000000.000000 0.296875 1.0000000.000000 0.312500 1.0000000.000000 0.328125 1.0000000.000000 0.343750 1.0000000.000000 0.359375 1.0000000.000000 0.375000 1.0000000.000000 0.390625 1.0000000.000000 0.406250 1.0000000.000000 0.421875 1.0000000.000000 0.437500 1.0000000.000000 0.453125 1.0000000.000000 0.468750 1.0000000.000000 0.484375 1.0000000.000000 0.500000 1.0000000.000000 0.515625 1.0000000.000000 0.531250 1.0000000.000000 0.546875 1.0000000.000000 0.562500 1.0000000.000000 0.578125 1.0000000.000000 0.593750 1.0000000.000000 0.609375 1.0000000.000000 0.625000 1.0000000.000000 0.640625 1.0000000.000000 0.656250 1.0000000.000000 0.671875 1.0000000.000000 0.687500 1.0000000.000000 0.703125 1.0000000.000000 0.718750 1.0000000.000000 0.734375 1.0000000.000000 0.750000 1.0000000.000000 0.765625 1.0000000.000000 0.781250 1.0000000.000000 0.796875 1.0000000.000000 0.812500 1.0000000.000000 0.828125 1.0000000.000000 0.843750 1.0000000.000000 0.859375 1.0000000.000000 0.875000 1.0000000.000000 0.890625 1.0000000.000000 0.906250 1.0000000.000000 0.921875 1.0000000.000000 0.937500 1.0000000.000000 0.953125 1.0000000.000000 0.968750 1.0000000.000000 0.984375 1.0000000.000000 1.000000 1.0000000.015625 1.000000 0.9843750.031250 1.000000 0.9687500.046875 1.000000 0.9531250.062500 1.000000 0.9375000.078125 1.000000 0.9218750.093750 1.000000 0.9062500.109375 1.000000 0.8906250.125000 1.000000 0.8750000.140625 1.000000 0.8593750.156250 1.000000 0.8437500.171875 1.000000 0.8281250.187500 1.000000 0.8125000.203125 1.000000 0.7968750.218750 1.000000 0.7812500.234375 1.000000 0.7656250.250000 1.000000 0.7500000.265625 1.000000 0.7343750.281250 1.000000 0.7187500.296875 1.000000 0.7031250.312500 1.000000 0.6875000.328125 1.000000 0.6718750.343750 1.000000 0.6562500.359375 1.000000 0.6406250.375000 1.000000 0.6250000.390625 1.000000 0.6093750.406250 1.000000 0.5937500.421875 1.000000 0.5781250.437500 1.000000 0.5625000.453125 1.000000 0.5468750.468750 1.000000 0.5312500.484375 1.000000 0.5156250.500000 1.000000 0.5000000.515625 1.000000 0.4843750.531250 1.000000 0.4687500.546875 1.000000 0.4531250.562500 1.000000 0.4375000.578125 1.000000 0.4218750.593750 1.000000 0.4062500.609375 1.000000 0.3906250.625000 1.000000 0.3750000.640625 1.000000 0.3593750.656250 1.000000 0.3437500.671875 1.000000 0.3281250.687500 1.000000 0.3125000.703125 1.000000 0.2968750.718750 1.000000 0.2812500.734375 1.000000 0.2656250.750000 1.000000 0.2500000.765625 1.000000 0.2343750.781250 1.000000 0.2187500.796875 1.000000 0.2031250.812500 1.000000 0.1875000.828125 1.000000 0.1718750.843750 1.000000 0.1562500.859375 1.000000 0.1406250.875000 1.000000 0.1250000.890625 1.000000 0.1093750.906250 1.000000 0.0937500.921875 1.000000 0.0781250.937500 1.000000 0.0625000.953125 1.000000 0.0468750.968750 1.000000 0.0312500.984375 1.000000 0.0156251.000000 1.000000 0.0000001.000000 0.984375 0.0000001.000000 0.968750 0.0000001.000000 0.953125 0.0000001.000000 0.937500 0.0000001.000000 0.921875 0.0000001.000000 0.906250 0.0000001.000000 0.890625 0.0000001.000000 0.875000 0.0000001.000000 0.859375 0.0000001.000000 0.843750 0.0000001.000000 0.828125 0.0000001.000000 0.812500 0.0000001.000000 0.796875 0.0000001.000000 0.781250 0.0000001.000000 0.765625 0.0000001.000000 0.750000 0.0000001.000000 0.734375 0.0000001.000000 0.718750 0.0000001.000000 0.703125 0.0000001.000000 0.687500 0.0000001.000000 0.671875 0.0000001.000000 0.656250 0.0000001.000000 0.640625 0.0000001.000000 0.625000 0.0000001.000000 0.609375 0.0000001.000000 0.593750 0.0000001.000000 0.578125 0.0000001.000000 0.562500 0.0000001.000000 0.546875 0.0000001.000000 0.531250 0.0000001.000000 0.515625 0.0000001.000000 0.500000 0.0000001.000000 0.484375 0.0000001.000000 0.468750 0.0000001.000000 0.453125 0.0000001.000000 0.437500 0.0000001.000000 0.421875 0.0000001.000000 0.406250 0.0000001.000000 0.390625 0.0000001.000000 0.375000 0.0000001.000000 0.359375 0.0000001.000000 0.343750 0.0000001.000000 0.328125 0.0000001.000000 0.312500 0.0000001.000000 0.296875 0.0000001.000000 0.281250 0.0000001.000000 0.265625 0.0000001.000000 0.250000 0.0000001.000000 0.234375 0.0000001.000000 0.218750 0.0000001.000000 0.203125 0.0000001.000000 0.187500 0.0000001.000000 0.171875 0.0000001.000000 0.156250 0.0000001.000000 0.140625 0.0000001.000000 0.125000 0.0000001.000000 0.109375 0.0000001.000000 0.093750 0.0000001.000000 0.078125 0.0000001.000000 0.062500 0.0000001.000000 0.046875 0.0000001.000000 0.031250 0.0000001.000000 0.015625 0.0000001.000000 0.000000 0.0000000.984375 0.000000 0.0000000.968750 0.000000 0.0000000.953125 0.000000 0.0000000.937500 0.000000 0.0000000.921875 0.000000 0.0000000.906250 0.000000 0.0000000.890625 0.000000 0.0000000.875000 0.000000 0.0000000.859375 0.000000 0.0000000.843750 0.000000 0.0000000.828125 0.000000 0.0000000.812500 0.000000 0.0000000.796875 0.000000 0.0000000.781250 0.000000 0.0000000.765625 0.000000 0.0000000.750000 0.000000 0.0000000.734375 0.000000 0.0000000.718750 0.000000 0.0000000.703125 0.000000 0.0000000.687500 0.000000 0.0000000.671875 0.000000 0.0000000.656250 0.000000 0.0000000.640625 0.000000 0.0000000.625000 0.000000 0.0000000.609375 0.000000 0.0000000.593750 0.000000 0.0000000.578125 0.000000 0.0000000.562500 0.000000 0.0000000.546875 0.000000 0.0000000.531250 0.000000 0.0000000.515625 0.000000 0.0000000.500000 0.000000 0.000000

代码：

//本程序的目的是改变jet到gray#include <stdlib.h>#include <stdio.h>#include <opencv2/core/core.hpp>#include <opencv2/highgui/highgui.hpp>#include <opencv2/imgproc/imgproc.hpp>using namespace cv;#include <iostream>using namespace std;int getgray(Mat jet, Vec3b color){double distance[256];for (int i = 0; i< 256; i++){double b = (color[0]*1.0/255-jet.at<Vec3f>(i, 0)[0])*(color[0]*1.0/255-jet.at<Vec3f>(i, 0)[0]);double g = (color[1]*1.0/255-jet.at<Vec3f>(i, 0)[1])*(color[1]*1.0/255-jet.at<Vec3f>(i, 0)[1]);double r = (color[2]*1.0/255-jet.at<Vec3f>(i, 0)[2])*(color[2]*1.0/255-jet.at<Vec3f>(i, 0)[2]);distance[i] = b+g+r;}int re = 0;for (int i = 1; i< 256; i++){if (distance[i]< distance[re]){re = i;}}return re;}int main(){//读取jetFILE *fp = fopen("jet.txt", "r");if (!fp) {cout << "cannot open file!\a"<< endl;return -1;}Mat jet = Mat(256, 1, CV_32FC3, Scalar::all(0));double r, g, b;int line = 0;char token[100];while(!feof(fp)){token[0] = NULL;fgets(token, 100, fp);//cout<<token<<endl;char tmp[9], tmp2[9], tmp3[9];for (int i = 0; i<8; i++){tmp[i] = token[i];}tmp[8] = '0';for (int i = 9; i<17; i++){tmp2[i-9] = token[i];}tmp2[8] = '0';for (int i = 18; i<26; i++){tmp3[i-18] = token[i];}tmp3[8] = '0';r = atof(tmp);g = atof(tmp2);b = atof(tmp3);//cout<<r<<"\t"<<g<<"\t"<<b<<endl;assert(line<256);jet.at<Vec3f>(line, 0) = Vec3f(b, g, r);line++;}//读取图片string name[]  ={"candies", "draws", "girls", "seal", "sheep", "taxi"};for (int seg = 0; seg< name->length(); seg++){string realname = "input/"+name[seg]+".png";string outputname = "output/"+name[seg]+"_gray.png";Mat color = imread(realname);Mat gray = Mat(color.rows, color.cols, CV_8UC1, Scalar::all(0));for (int i = 0; i< color.rows; i++){cout<<"%"<<i*100/color.rows<<endl;for (int j = 0; j< color.cols; j++){gray.at<uchar>(i, j) = getgray(jet, color.at<Vec3b>(i, j));}}imshow("gray", gray);waitKey(33);imwrite(outputname, gray);}return 0;}

以下是把gray转换为obj文件（默认灰度值代表深度值）

代码：

//本程序的目的是输出obj#include <opencv2/core/core.hpp>#include <opencv2/highgui/highgui.hpp>#include <opencv2/imgproc/imgproc.hpp>using namespace cv;#include <iostream>#include <fstream>using namespace std;void getmtl(string name){ofstream obj("output/"+name+".mtl");obj<<"\nnewmtl material_0\n"<<"Ka 0.200000 0.200000 0.200000\n"<<"Kd 1.000000 1.000000 1.000000\n"<<"Ks 1.000000 1.000000 1.000000\n"<<"Tr 1.000000\n"<<"illum 2\n"<<"Ns 0.000000\n"<<"map_Kd ./"<<name<<".png\n";obj.close();}void getobj(Mat gray, string name){assert(gray.type() == CV_8UC1);ofstream obj("output/"+name+".obj");//第一步，写点//从上到下，从左到右//范围是-1到1//mtlobj<<"\nmtllib ./"<<name<<".mtl"<<"\n\n";getmtl(name);int rows = gray.rows;int cols = gray.cols;int z = 255*5;cout<<"points\n";for (int i = 0; i< rows; i+=10){for (int j = 0; j< cols; j+=10){double x = j*1.0/cols;double y = 1-i*1.0/rows;double zz = gray.at<uchar>(i, j)*1.0/z;obj<<"v "<<x<<" "<<y<<" "<<zz<<"\n";}}//第二步， 写材质obj<<"\nusemtl material_0"<<"\n\n";cout<<"textures\n";for (int i = 0; i< rows; i+=10){for (int j = 0; j< cols; j+=10){double s = j*1.0/cols;double t = 1-i*1.0/rows;obj<<"vt "<<s<<" "<<t<<"\n";}}//第三步， 写面obj<<"\n";cout<<"faces\n";rows = rows/10;cols = cols/10;for (int i = 0; i< rows-1; i++){for (int j = 0; j< cols-1; j++){//以(i, j)为顶点，会形成两个三角形//第一个是：(i, j), (i, j+1), (i+1, j+1)，索引是：i*cols+j+1//第二个是：(i, j), (i+1, j+1), (i+1, j)/*obj<<"f "<<(i*cols+j+1)<<"/"<<((i*cols+j+1))<<" "<<(i*cols+j+1+1)<<"/"<<((i*cols+j+1+1))<<" "<<((i+1)*cols+j+1+1)<<"/"<<((i+1)*cols+j+1+1)<<"\n";obj<<"f "<<(i*cols+j+1)<<"/"<<((i*cols+j+1))<<" "<<((i+1)*cols+j+1+1)<<"/"<<((i+1)*cols+j+1+1)<<" "<<((i+1)*cols+j+1)<<"/"<<((i+1)*cols+j+1)<<"\n";*/obj<<"f "<<(i*cols+j+1)<<"/"<<((i*cols+j+1))<<" "<<((i+1)*cols+j+1+1)<<"/"<<((i+1)*cols+j+1+1)<<" "<<(i*cols+j+1+1)<<"/"<<((i*cols+j+1+1))<<"\n";obj<<"f "<<(i*cols+j+1)<<"/"<<((i*cols+j+1))<<" "<<((i+1)*cols+j+1)<<"/"<<((i+1)*cols+j+1)<<" "<<((i+1)*cols+j+1+1)<<"/"<<((i+1)*cols+j+1+1)<<"\n";}}obj<<"\n";obj.close();}int main(){string name[]  ={"candies", "draws", "girls", "seal", "sheep", "taxi"};for (int seg = 0; seg<6; seg++){Mat test = imread("output/"+name[seg]+"_gray.png", 0);getobj(test, name[seg]);}return 0;}

over。enjoy it。