Peak value of histogram used to find corresponding values in original data

[novice_user]

Hi Ankita

Thanks a lot for the other VI. I am still trying to figure it out, but it would be kind of you will give me your number and I will give you a call when it is convenient for you to receive calls. I understand you are in the discussion forum department but if you could that would be great. Till then I will try to understand the VI which you have sent me. Also I did not understand what is SSP.

Thanks once again. I appreciate your help.

[Ankita A.]

Hi,

You are right in stating that I am in the Discussion Forums department. Unfortunately, I do have have a phone extension but I support customers via our Discussion Forum support.

Since you are trying to understand the recent VI that I sent you, please open the Context Help Window, and see the help for all the functions used in this VI. You can create indicators to see what each function in this VI is doing. If you need any help in understanding any specific function, please let me know and I will try to explain via Discussion Forum posts.

As a starting point, this VI plots a histogram based on the Intensity values. Now it finds out the histogram values lying within the Intensity range you specify. Withing these Histogram values, the
highest value of the histogram is found, the corresponding intensity to this highest value is located on the first graph and an index of wavelength values returned.

Regards,
Ankita A.
SSP is abbreviation for "Standard Service program". More information about SSP can be found at
http://digital.ni.com/manuals.nsf/webAdvsearch/34F8DB52247E1D2886256E94006D7B40?OpenDocument&vid=niwc&node=132100_US

[novice_user]

Hi
I tried running the vi using the help of the Context Help Window. I understand the basic flow of the program but I have an issue with Histogram indicator and the Range Histogram indicators. The Range Histogram remains 0 in most of the cases I tried and Histogram shows 0 in the scroll bar menu box but shows different values for each set of data. These values or what they indicated to I did not understand. Also in the wavelength array indicator it is the min wavelength displayed but in the intensity array indicator I dont know which value is displayed.

I am attaching a few of the data files which might give you the idea about what I am saying.

If I could discuss same topic over the phone with you I guess it will be sorte
d much quicker and you could get your point across much clearly. The phone group says since you have been around with this problem it is better for you to solve it, and it would take less time through the phone.

Also regarding the SSP thing I am a student and this aspect might have been surely managed by my Univ. By the way I am in the University of North Texas. If it is for an individual who needs to enroll I will surely look into it in more detail once this semester is over.

Thanks once again for all the you providing. I would give you 5 stars in your overall help and service.

[Arun_V]

Hey Novice User,

I was going through the thread and I wanted you to know that NI offers some quality courses on LabVIEW Basics,that one can take as a novice user. You can find more information on ni.com/training and the beauty is you get the Application Engineer themselves as the instructor. I was in one of the classes and my efficiency with LabVIEW increased exponentially. Best of Luck!

[Ankita A.]

The wavelength array indicator displays the first column of the data file. The Intensity array indicator displays the second column of the data file.

Histogram and Range Histogram are array indicators. Histogram indicator just displays the frequency values for each intensity bin. Range histogram indicator takes a subset of the Histogram frequency values and displays only the frequency values for the bins that lie within the Intensity ranges you specified. To view Histogram and Range Histogram indicators, either expand them so you could see the whole array or click with the mouse on the Index display of these indicators. The value of the Range Histogram indicator would depend on the range of intensities you specify in the "Max
Intensity for peak detection" and "Min Intensity for peak detection" controls.

The values that you see seeing in the Histogram array indicator are the values corresponding to the intensity bins. Since you have 512 bins which divide the intensities from -111 to 55257, each bin would have size of (55257+111)/512)=108 approximately. The Histogram array value for index 0 would be the number of intensities occuring between -111 and -3, Histogram array value for index 1 would be the number of intensities occuring between -2 and 105...refer LabVIEW help for Histogram function for more information.

As for the issue of conversing on phone, unfortunately that is not how our support structure works (otherwise I would love to get 5 stars). Please let me know if you have any other problems with this issue, and I would try my best to help you out.

Regards,
Ankita A.

[novice_user]

Hi
The new vi which you built shows a max intensity of 14812.4 for the hd2 file. This corresponds to 16 different wavelengths since it falls between the 2 bins in the histogram like you explained which I have also shown in the right most columns of the excel file "Step by Step Build Up of a Histogram......xls". Similarly in the vi, "Wavelength corresponding to a particular Intensity value" indicator should show 16 values of wavelengths. I want this indicator to display these 16 values while it is showing just two even after expanding the indicator. Please will you tell me how to do that.

Thanks for all your help. I would not ask to converse with you and do it through the forum itself.

Thanks

[Ankita A.]

Hi,

Could you please attach the "Step by Step Build Up of a Histogram......xls" so I can have a better idea of what you are trying to convey.

Regards,
Ankita A.

[Ankita A.]

Hi,

In the latest VI I sent you, you see a frequency of 16 corresponding to the maximum intensity of 14812.4
This means that the bin in which 14812.4 lies, there are 16 wavelengths. The value 14812.4 is the lower limit of the BIN in which these 16 wavelengths lie but the value 14812.4 is not a intensity value from the original data set. So I am finding the closest value to 14812.4 that actually occurs in the data set (in this case it is 14815...shown in the "Next High Intensity" indicator) so I could find the wavelengths corresponding to the intesity value.
The two values of wavelength you see in the "wavelength corresponding to particular intensity value" array correspond to the value 14815 shown
in the "next high intensity" indicator.

Hope this helps,
Ankita A.

[novice_user]

Hi Ankita
What you explained this time cleared my doubt. I am also attaching that file which you asked for. The "next high intensity" indicator was going over my head earlier.

Thanks a lot