SiftGPU關於增加匹配對的數目問題

關於SiftGPU，有時候我們需要更多的匹配對的數目

兩種方式：

1，增加提取的特徵點的數目

2，特徵點的數目給定後，增加要提取的匹配對數目

參考SiftGPU的討論：

https://groups.google.com/forum/#!msg/vsfm/8jfizyvu8gc/C9VE5fkoawcJ

默認情況下，我們使用標準數據集測試得到：

現在我們做一些改動：

void SiftGPU::PrintUsage()
{
	std::cout
	<<"SiftGPU Usage:\n"
	<<"-h -help          : Parameter information\n"
	<<"-i <strings>      : Filename(s) of the input image(s)\n"
	<<"-il <string>      : Filename of an image list file\n"
	<<"-o <string>       : Where to save SIFT features\n"
	<<"-f <float>        : Filter width factor; Width will be 2*factor+1 (default : 4.0)\n"
	<<"-w  <float>       : Orientation sample window factor (default: 2.0)\n"
	<<"-dw <float>  *    : Descriptor grid size factor (default : 3.0)\n"
	<<"-fo <int>    *    : First octave to detect DOG keypoints(default : 0)\n"
	<<"-no <int>         : Maximum number of Octaves (default : no limit)\n"
	<<"-d <int>          : Number of DOG levels in an octave (default : 3)\n"
	<<"-t <float>        : DOG threshold (default : 0.02/3)\n"
	<<"-e <float>        : Edge Threshold (default : 10.0)\n"
	<<"-m  <int=2>       : Multi Feature Orientations (default : 1)\n"
	<<"-m2p              : 2 Orientations packed as one float\n"
	<<"-s  <int=1>       : Sub-Pixel, Sub-Scale Localization, Multi-Refinement(num)\n"
	<<"-lcpu -lc <int>   : CPU/GPU mixed Feature List Generation (defaut : 6)\n"
	<<"                    Use GPU first, and use CPU when reduction size <= pow(2,num)\n"
	<<"                    When <num> is missing or equals -1, no GPU will be used\n"
	<<"-noprep           : Upload raw data to GPU (default: RGB->LUM and down-sample on CPU)\n"
	<<"-sd               : Skip descriptor computation if specified\n"
	<<"-unn    *         : Write unnormalized descriptor if specified\n"
	<<"-b      *         : Write binary sift file if specified\n"
	<<"-fs <int>         : Block Size for freature storage <default : 4>\n"
    <<"-cuda <int=0>     : Use CUDA SiftGPU, and specifiy the device index\n"
	<<"-tight            : Automatically resize pyramid to fit new images tightly\n"
	<<"-p  <W>x<H>       : Inititialize the pyramids to contain image of WxH (eg -p 1024x768)\n"
	<<"-tc[1|2|3] <int> *: Threshold for limiting the overall number of features (3 methods)\n"
	<<"-v <int>          : Level of timing details. Same as calling Setverbose() function\n"
	<<"-loweo            : (0, 0) at center of top-left pixel (defaut: corner)\n"
	<<"-maxd <int> *     : Max working dimension (default : 2560 (unpacked) / 3200 (packed))\n"
	<<"-nomc             : Disabling auto-downsamping that try to fit GPU memory cap\n"
	<<"-exit             : Exit program after processing the input image\n"
	<<"-unpack           : Use the old unpacked implementation\n"
	<<"-di               : Use dynamic array indexing if available (defualt : no)\n"
	<<"                    It could make computation faster on cards like GTX 280\n"
	<<"-ofix     *       : use 0 as feature orientations.\n"
	<<"-ofix-not *       : disable -ofix.\n"
	<<"-winpos <X>x<Y> * : Screen coordinate used in Win32 to select monitor/GPU.\n"
    <<"-display <string>*: Display name used in Linux/Mac to select monitor/GPU.\n"
    <<"\n"
    <<"NOTE: parameters marked with * can be changed after initialization\n"
	<<"\n";
}

有一篇未開源的論文：