OpenCv SVM输出文件格式

Question

我正在实现自己的SVM，而不是使用OpenCV的svm类。我希望我的SVM用于保存其输出的XML文件，如果愿意，可以在将来由OpenCV的SVM加载和使用。我应该为此做些什么？

简而言之：OpenCV用来存储SVM输出的格式是什么？

Answer 1

您可以关注OpenCV的CvSVM :: write函数。

int i, var_count = get_var_count(), df_count, class_count; 
const CvSVMDecisionFunc* df = decision_func; 

cvStartWriteStruct(fs, name, CV_NODE_MAP, CV_TYPE_NAME_ML_SVM); 

write_params(fs); 

cvWriteInt(fs, "var_all", var_all); 
cvWriteInt(fs, "var_count", var_count); 

class_count = class_labels ? class_labels->cols : 
       params.svm_type == CvSVM::ONE_CLASS ? 1 : 0; 

if(class_count) 
{ 
    cvWriteInt(fs, "class_count", class_count); 

    if(class_labels) 
     cvWrite(fs, "class_labels", class_labels); 

    if(class_weights) 
     cvWrite(fs, "class_weights", class_weights); 
} 

if(var_idx) 
    cvWrite(fs, "var_idx", var_idx); 

// write the joint collection of support vectors 
cvWriteInt(fs, "sv_total", sv_total); 
cvStartWriteStruct(fs, "support_vectors", CV_NODE_SEQ); 
for(i = 0; i < sv_total; i++) 
{ 
    cvStartWriteStruct(fs, 0, CV_NODE_SEQ + CV_NODE_FLOW); 
    cvWriteRawData(fs, sv[i], var_count, "f"); 
    cvEndWriteStruct(fs); 
} 

cvEndWriteStruct(fs); 

// write decision functions 
df_count = class_count > 1 ? class_count*(class_count-1)/2 : 1; 
df = decision_func; 

cvStartWriteStruct(fs, "decision_functions", CV_NODE_SEQ); 
for(i = 0; i < df_count; i++) 
{ 
    int sv_count = df[i].sv_count; 
    cvStartWriteStruct(fs, 0, CV_NODE_MAP); 
    cvWriteInt(fs, "sv_count", sv_count); 
    cvWriteReal(fs, "rho", df[i].rho); 
    cvStartWriteStruct(fs, "alpha", CV_NODE_SEQ+CV_NODE_FLOW); 
    cvWriteRawData(fs, df[i].alpha, df[i].sv_count, "d"); 
    cvEndWriteStruct(fs); 
    if(class_count > 1) 
    { 
     cvStartWriteStruct(fs, "index", CV_NODE_SEQ+CV_NODE_FLOW); 
     cvWriteRawData(fs, df[i].sv_index, df[i].sv_count, "i"); 
     cvEndWriteStruct(fs); 
    } 
    else 
     CV_ASSERT(sv_count == sv_total); 
    cvEndWriteStruct(fs); 
} 
cvEndWriteStruct(fs); 
cvEndWriteStruct(fs); 

这里是如何创建一个CvFileStorage并将其保存到磁盘：

const char* filename = "/xxx/yyy/zzz"; 
const char* modelname = "svm"; 
CvFileStorage* fs = cvOpenFileStorage(filename, 0, CV_STORAGE_WRITE); 
if (fs) { 
    write(fs, modelname); 
} 
cvReleaseFileStorage(&fs); 

通过这样做，你可以选择将模型保存为XML或YAML格式，并使用CvSVM :: read（）加载模型文件。希望这可以帮助。