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[Asking for solution! No code!] Column detection with/without stereo vision

asked 2018-09-28 03:36:15 -0600

updated 2018-09-28 04:59:07 -0600

Hello guys, I am sorry to ask without code. I tried to calibrate my stereo fisheyes and failed, tried for a week to do it. Rectification and stereo calibrate is bad somehow. Anyways, my plan is for the drones. Drone will have one or two cameras and it will fly on a vineyard. As you know, vineyard is basically in column shape. So when flying over a column, I need to understand that I am in the middle of the column . Otherwise it means that I need to go left or right. Example:

Columns

If you can give me some hints I'd be so grateful. I think that if I had depth image I can take gradients to see if my rotation and location is correct or not. Or I can do some segmentation and split the images and get different gradients. It is so confusing. I don't want code, I just want some ideas. Thanks to all, great day.

Edit 1: I am adding colored undistorted pairs and grayscale undistorted pairs with disparity(because of failed stereo calibration and rectification): colored pair grayscale with undistortion and disparity

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please put your image here , not on dropbox.

berak gravatar imageberak ( 2018-09-28 03:42:30 -0600 )edit

Can't do, everytime I upload image it doesn't add it. Sorry. I made it public so at least people can see the images.

yeser gravatar imageyeser ( 2018-09-28 03:51:37 -0600 )edit

resaved as jpg, and uploaded.

(there's a 1mb limit for images on this site, so please also respect other ppls bandwidth)

berak gravatar imageberak ( 2018-09-28 04:00:53 -0600 )edit

I didn't know that. Thanks for editing, I'm grateful.

yeser gravatar imageyeser ( 2018-09-28 04:16:52 -0600 )edit

to get back on topic, - what's the reason to use fisheye lenses here ?

(i doubt, that you need a real large fov for this task, and the distortions clearly get in the way.)

also, even if you can't do a proper stereo calibration (yea, hard !) , you should still try to calibrate the single cameras, so you can undistort the images

berak gravatar imageberak ( 2018-09-28 04:28:40 -0600 )edit
1

My drone should see the down and the front at the same time for landing(with aruco) and also I need to use it for column detection. I can't stereo calibrate but I did it single and undistorted the image. But even if I do that, it is a mystery for me to solve the rest. Fisheye for wide angle for both bottom and front that's all. Other than there is no reason. I am editing the post so you can see the undistorted images.

yeser gravatar imageyeser ( 2018-09-28 04:56:48 -0600 )edit

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answered 2018-09-28 06:05:43 -0600

berak gravatar image

updated 2018-09-28 06:25:55 -0600

i got at least one idea for you, it's also far more primitive, than your prev. attempts:

  • use only a small roi in the direction you're going
  • threshold/morphology/blurring. exploit, that the top of the vine bushes are lighter than the bg
  • findContours() or simply findNonzero(), followed by PCA analysis
  • stay over the "white parts", and follow the green arrow !

image description

it's way over the top, but you might also want to read the pushbroom stereo paper

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Thank you so much for the work and guide. I will try and update here. ^^

yeser gravatar imageyeser ( 2018-09-28 11:38:56 -0600 )edit
1

again, it's more an entirely sloppy, tongue in cheek post (what have you tried, what did you miss ?)

it's all "clickbait". i'm mainly trying to lure you into reading the pushbroom paper !

berak gravatar imageberak ( 2018-09-28 11:44:53 -0600 )edit

I was trying for stereo calibration whole time. Maybe I should ask is there any method to rectificate stereo images without stereo calibration? I am sorry for creating a "clickbait" post but I really have no idea what should I do. Thank you for guiding me somewhere, at least I have a starting point now.

yeser gravatar imageyeser ( 2018-10-01 01:24:28 -0600 )edit
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wait, the "clickbait" was about my post, not yours ! (sorry for being misleading)

stereo calibration is hard, ppl usually need a few attempts to get a good rms(<0.5), and with fisheye it's even harder.

note, that you can also try hartley's method without stereo calibration

berak gravatar imageberak ( 2018-10-01 02:31:46 -0600 )edit

@berak, again thank you so much for giving ideas. I am closing the problem because I used something to get. At first I should say that I have stereo wide angle cameras instead of fisheye(less fov) and it is quite good now. I am also using DGM library to extract green parts and using it to support depth image. My results are not bad but I am still working on it. I am just using addWeighted for combining images and I have single channel. I just run hough lines for big lines and I am cheking it's rotation to see if it is on the right way. And I am smoothing with average on close lines(if found lines are closer than 100 pixel, I can get average). I will make an update on that and of course share my code if I can. Thanks again

yeser gravatar imageyeser ( 2018-10-18 13:51:18 -0600 )edit

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Asked: 2018-09-28 03:36:15 -0600

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Last updated: Sep 28 '18