Re: [R] no true negative data, need roc curve

Hi, again i had small clarification regarding the discussion. I had 6 images of two threshold test, so can i plot 6 roc for each individual image? or can i plot two roc curve (threshold 1 all images summed up and similar to threshold 2)? which is the correct one? Please clarify me in this re

Re: [R] no true negative data, need roc curve

Hi, Thanks a lot. I learned that the ROC used in my area was a modified one like you mentioned, but i want to stick to that if i want to put my result to such community. I was new to this topic and R, you guided me a lot and made me to understand. thank you.

Re: [R] no true negative data, need roc curve

This is not a typo error, in feature detection when it was not able to calculate 'tn' then they are using this formula and there are more papers (referred journal) which quote same formula. In the same manner i had also got the tp, fp and fn. Based on it can some one suggest me to plot the ROC curv

Re: [R] no true negative data, need roc curve

Hi, thanks for the quick response, but as i said in my case due to two different threshold the detected features will differ. Moreover, there is some standard /refined/ formula in calculating the tpr and fpr. herewith i had attached the refined formula from a standard international journal h

Re: [R] no true negative data, need roc curve

TN=0 in all cases, i had only tp, fp and fn for 6 images (two sets). suggest me how plot the roc curve. -- View this message in context: http://r.789695.n4.nabble.com/no-true-negative-data-need-roc-curve-tp4640474p4640558.html Sent from the R help mailing list archive at Nabble.com.

Re: [R] no true negative data, need roc curve

or do you not know TN (N)? On 16.08.2012, at 11:51, vjyns wrote: > Hi, > > I want to plot ROC curve for my detection algorithm which detects > features in different images at two different thresholds. > > 6 different images used and obtained tp, fp and fn. No tn in

[R] no true negative data, need roc curve

Hi, I want to plot ROC curve for my detection algorithm which detects features in different images at two different thresholds. 6 different images used and obtained tp, fp and fn. No tn in my case. in first threshold run i obtained 6 values of tp,fp and fn. In second threshold run agian i got

[R] Plot ROC using TP,FP AND FN alone

Hi, I want to plot ROC curve for my detection algorithm which is used to detect features in image. I had obtained true positive, false positive and false negative from the algorithm. There is no true negative in my case. I had run the algorithm for 6 images so i got 6 number of TP,FP