2017-09-18 01:27:26 -0600
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2017-01-06 07:32:07 -0600
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2014-12-03 01:15:30 -0600
| asked a question | Write data to text file Hi, I am trying to read a ".csv" file that contains double valued data like this: 1 0.0922279 0.0977822 0.0567845 0.0308806 0.0491464 0.0436114
1 0.277745 0.130502 0.118348 0.0365346 0.0669739 0.00924114
1 0.137181 0.140128 0.116455 0.122226 0.151289 0.129282
1 0.182825 0.0810142 0.0811148 0.0588809 0.147732 0.0410181
The above is just an example. The real ".csv" file is 269 row by 3780 column (269 x 3780). I try to read the csv file, put the values in a Mat and then write that Mat to another file called "data.txt". However, when I open the data.txt nothing is written except a value of 1. This is obviously wrong as, the data to the file would have contained the same values of the original "csv" file. This is the code: #include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/ml/ml.hpp> // for CvMLData
#include <iostream>
#include <fstream>
using namespace std;
using namespace cv;
int main()
{
ofstream data("data.txt"); //
CvMLData mlData;
mlData.read_csv("HOG_data.csv"); // File containing 269 row by 3780 column
if(mlData.get_values() == nullptr)
{
cout << "Unable to open file !" << endl;
return 1;
}
//const Mat m = mlData.get_values(); <---Also tried this;
const CvMat *m = mlData.get_values();
Mat dataset;
dataset = m;
for(int i = 0; i < dataset.rows; i++)
{
for(int j =0; j < dataset.cols; j++)
{
data << dataset.at<float>(i,j) << " ";
}
data << endl;
}
waitKey();
return 0;
}
Any suggestions or something i've probably overlooked ? |
2014-11-18 00:36:22 -0600
| asked a question | Computing Histogram of Oriented Gradients Hi, In order to understand the Histogram of Oriented Gradients (HOG) features proposed by Dalal and Triggs, I have opted to hard code it without using openCV's HOGDescriptor. Here is some relevant code that i tried to implement HOG: void hog::hog_process(Mat &direction) // direction is the gradient direction matrix
{
Size blockSize(8,8);
Size cellSize(4,4);
vector<Mat> block;
Size s = direction.size();
Mat cell_eightPx;
Mat cell_fourPx;
// Essentially split the image into 8 by 8 cells. HOG processing of each block should be essiantially here.
// the 8 by 8 cells are then split again into 4 by 4 cells
for(int col = 0; col < direction.rows; col += blockSize.height)
{
for(int row = 0; row < direction.cols; row += blockSize.width)
{
Rect rect= Rect(row, col,blockSize.width,blockSize.height);
cell_eightPx = Mat(direction,rect); // Get a 8 by 8 cell from the gradient direction matrix.
//**********COMPUTE 9 bin gradient direction histogram of the 8 by 8 cell here !!! ****
for(int i = 0; i < cell_eightPx.rows; i += cellSize.height)
{
for(int j = 0; j < cell_eightPx.cols; j += cellSize.width)
{
Rect rect_fourPx = Rect(i,j,cellSize.width,cellSize.height); // 4 by 4 rectangle size
cell_fourPx = Mat(cell_eightPx,rect_fourPx); // create a 4 by 4 cell from gradient direction matrix (cell_eightPx)
gradientHist(cell_fourPx); // Calculate gradient histogram of the 4 by 4 cell. (Function call)
cell_fourPx.deallocate(); // clear the cell.
}
}
}
}
}
Here is the function gradientHist() to calculate the 9 bin histogram for the HOG features: void hog::gradientHist(Mat &cell_fourPx)
{
Mat hist;
ofstream feature("Hist_Values.csv",std::ofstream::app);
// create a 9 bin histogram with range from 0 t0 180 for HOG descriptors.
int histSize = 9;
float range[] = {0,180};
const float *histRange = {range};
bool uniform = true;
bool accumulate = false;
calcHist(&cell_fourPx, 1, 0,Mat(),hist, 1, &histSize, &histRange, uniform, accumulate); //Calculate the 9 bin histogram.
normalize(hist, hist, 0, 0, NORM_MINMAX, -1, Mat());
for(int i = 0; i < histSize; i++)
{
feature << hist.at<float>(i) << ","; // Output the value of HOG to a csv file
}
}
However, OpenCV is telling me: unsupported format or combination of formats () in calcHist, file....line 1219....histogram.cpp:1219:
error(-210) in function calcHist
perhaps I've overlooked something ? Any Suggestions/Ideas would be appreciated. Thanks in advance... |
2014-11-17 01:50:42 -0600
| asked a question | Problem with computing Histogram of Oriented Gradients (HOG) Hi, In order to understand the mechanics of Histogram of Oriented Gradients proposed by Dalal and Triggs, I have tried to hard code the HOG algorithm. However I am having some problems. It says OpenCV error: Unsupported format or combination of formats () in calcHist....
error: (-210) in function calcHist
I am not quite sure what format of the function argument that is not right. This is the code: void hog::hog_process(Mat &direction) // direction is a 128 by 64 gradient direction matrix.
{
Size blockSize(8,8);
Size cellSize(4,4);
vector<Mat> block;
Size s = direction.size();
Mat cell_eightPx;
Mat cell_fourPx;
// Essentially split the image into 8 by 8 cells. HOG processing of each block should be essiantially here.
// the 8 by 8 cells are then split again into 4 by 4 cells
for(int col = 0; col < direction.rows; col += blockSize.height)
{
for(int row = 0; row < direction.cols; row += blockSize.width)
{
Rect rect= Rect(row, col,blockSize.width,blockSize.height);
cell_eightPx = Mat(direction,rect); // Get a 8 by 8 cell from the gradient direction matrix.
//**********COMPUTE 9 bin gradient direction histogram of the 8 by 8 cell here !!! ****
for(int i = 0; i < cell_eightPx.rows; i += cellSize.height)
{
for(int j = 0; j < cell_eightPx.cols; j += cellSize.width)
{
Rect rect_fourPx = Rect(i,j,cellSize.width,cellSize.height); // 4 by 4 rectangle size
cell_fourPx = Mat(cell_eightPx,rect_fourPx); // create a 4 by 4 cell from gradient direction matrix (cell_eightPx)
gradientHist(cell_fourPx); // Function call, Calculate gradient histogram of the 4 by 4 cell.
cell_fourPx.deallocate(); // clear the cell.
}
}
}
}
}
After partitioning the image with 4 by 4 cells as the above code the 9 bin histogram calculation is as follows: void hog::gradientHist(Mat &cell_fourPx)
{
Mat hist;
ofstream feature("Hist_Values.csv",std::ofstream::app);
// create a 9 bin histogram with range from 0 t0 180 for HOG descriptors.
int histSize = 9;
float range[] = {0,180};
const float *histRange = {range};
bool uniform = true;
bool accumulate = false;
calcHist(&cell_fourPx, 1, 0,Mat(),hist, 1, &histSize, &histRange, uniform, accumulate); //Calculate the 9 bin histogram.
normalize(hist, hist, 0, 0, NORM_MINMAX, -1, Mat());
for(int i = 0; i < histSize; i++)
{
feature << hist.at<float>(i) << ","; // Output the value of HOG to a csv file
}
}
Any suggestions/ directions are very much welcomed. I may have overlooked something. Thanks in advance. |
2014-10-16 02:13:25 -0600
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2014-10-16 02:12:57 -0600
| commented answer | Computing gradient direction of image Hi rwong, Thank you very much for your reply and suggestions. I understand it now. After making some changes as you suggested I have managed to correct the problems. Thank again. |
2014-10-15 03:14:56 -0600
| asked a question | Computing gradient direction of image Hi, I am trying to calculate the gradient direction of an image. I tried the following function: Mat computeArcTan(Mat &dst1, Mat &dst2)
{
Mat angle;//(dst1.rows,dst1.cols,CV_32F);
ofstream myFile("angle.csv");
const double pi = 3.14159;
for(int row = 0; row < dst1.rows; row++)
{
for(int col = 0; col < dst1.cols; col++ )
{
//angle.at<uchar>(row,col)=(double)atan2(dst1.at<uchar>(row,col),dst2.at<uchar>(row,col)*180/pi);
angle.push_back((double)atan2(dst1.at<uchar>(row,col),dst2.at<uchar>(row,col))*180/pi);
myFile << angle.at<double>(row,col) <<",";
}
myFile << endl;
}
return angle;
}
the dst1 and dst2 are the gradient of x and y direction. However, I believe I am not getting the correct direction values. The values printed in the csv file is a repetition of values of 0, 18.435, 45 and 71.3872. When i checked with matlab, it is totally wrong. I know openCV has the function cartToPolar() but I'm trying to hard code it just to understand the process behind it. Any Ideas or direction/suggestion on what am i doing wrong ? thanks, |