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stereolabs / zed-matlab

ZED SDK interface sample for Matlab

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obtain depth map from only left and right color images

nikky4D opened this issue · comments

commented

Hi,

I have the left and right images from the zed explorer. I would like to get the depth images of these scenes in MATLAB. Unfortunately, I don't have access to the environment where the images were taken. Is there a way to get the depth images when I only have the left and right images from the zed?

I have the camera parameters fx, fy, cx,cy, baseline.

Right now, I am assuming these images are already rectified. So, I can get the disparity map, and calculate the depth like so:

disparityMap = disparity(img_left, img_right);
figure;imshow(disparityMap,[0, 100],'InitialMagnification', 50);

%% By stereoLabs calculation, Z is:
fx_left = 699.291; baseline = 119.923;
Z = (fx_left .* baseline ) ./ (1.*disparityMap);
figure;imshow(Z,[0, 5000]);

is this the correct method?

Thanks

commented

Hi,
your formulae is correct (f*B/disp) but ZED Explorer gives unrectified images, therefore you won't have good results.

2 solutions :

  • Use the parameters from the calibration file (fx/y, cx/y, rx,cv,rz) and create a rectification map and a new camera matrix. You can then ingest the rectified images in disparity() function from matlab. I don't know how to do it in Matlab.
  • Use the ZED SDK to get rectified images (retrieveImage()) and new calibration parameters (getCameraInformation().calibration_parameters) you can directly ingest in disparity()

/OB/

commented

Hi,
I am using ZED2 camera and using the APIs as mentioned below to fetch the depth. And then using the point cloud to calculate depth.

  1. zed.retrieveImage(image, VIEW::LEFT);
  2. zed.retrieveMeasure(depth, MEASURE::DEPTH); to fetch depthmap.
  3. zed.retrieveMeasure(point_cloud, MEASURE::XYZRGBA);
    float distance = sqrt(point3D.xpoint3D.x + point3D.ypoint3D.y + point3D.z*point3D.z);

I have few questions as:

  1. Is there any reason to not use these APIs and calculating with disparity?
  2. Why we are using only left view? Should I use both right and left view?
commented

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