4arbouch's profile - activity

Thanks for your reponse :) I'll look if I can find something interesting .

Thank you :) it works :D

I'am actually building an application on android using Samsung galaxy tab 10.1. I want to get the value of the luminance using the back Camera of the device.

The problem is that there is not a light sensor in the back of the device to just get the value that the light sensor gives to us . So I have to do it manually, in fact, I have to take frames in real time and for each frame I calculate the mean of the grayscale image, there is still a problem with that: With this method you will have false values because of the auto-correction of the camera and white balancing.

For instance, if you point the camera in front of a very bright source, the camera will focus on the bright area and all the area that surronds the bright point will became very dark so that the mean of the grayscale image gives us a false value ( it will not be very high in this case because there is dark area). I searched about method in the android API that disable such corrections but I do not found something interesting.

So, the question is: Is there a method in openCV than can help me having a nice estimation about the amount of light that enter to the back camera or some method that can help me accessing the parameters of the camera so that I manipulate them to , maybe , help me in the estimation of the luminance ?

Let me know if something is unclear ;) Thank you :D

Hi , Thank you for your response :) But if we use loops, this will considerably increases the complexity of the program and the application will be very slow in processing especially when doing such image processing in real time, what I'am actually doing :) So I asked myself if there is a method in openCV that I can use to do such operations as described in the comment below . Thank you :)

Hi , My goal is not to calculate the mean of all the image, I want to calculate the mean of some regions of the images. In fact , I want to calculate the mean value of the non zeros pixels , When I use Core.mean the 0 values of the pixels will contribute in this calculation ! So I asked my self if there is a method in openCV that can help me doing this. : Calculate the mean value of just some pixels on the image ( for me the values that are different of 0 ) . Thank you :)

Hello,

I'am actually working in a project on android in which I want to extract some specific pixel values (according to a condition) and having these values in a vector. I will use this vector of the chosen pixels to do some operation ( the mean value for exemple ) , Is there a method in OpenCV that can help me doing this ?

Thank you :)