Depth information acquisition method and device

A depth information acquisition method, including the following steps:

• S100:
• determining a relative geometric position relationship between a pixel of a depth map generated by a ToF camera and pixels of images of left and right cameras in a binocular camera, and internal parameters of the ToF camera and the left and right cameras;
• S200:
• collecting the depth map generated by the ToF camera and the images of the two cameras;
• S300:
• converting the depth map into a binocular disparity value between corresponding pixels in the images of the two cameras;
• S400:
• mapping, by using the converted binocular disparity value, any pixel in the depth map generated by the ToF camera to corresponding pixel coordinates of the images of the two cameras to obtain a sparse disparity map;
• and
• S500:
• performing step S400 on all pixels in the depth map generated by the ToF camera to obtain a dense disparity map, thereby obtaining more accurate and denser depth information;
• or inversely calibrating the depth map generated by the ToF camera collected in step S200 with the sparse disparity map, thereby outputting more accurate depth information,
• wherein step S300 further includes the following sub-steps:
• S3001:
• representing the depth map generated by the ToF camera by a grayscale image, a depth value being linear with a distance:
• dt=αGt+β, wherein dt is the depth value measured by the ToF camera, Gt is a grayscale value, and α and β are coefficients;
• S3002:
• obtaining, by binocular vision, spatial distance information by calculating the disparity value between the left and right images, a depth calculation formula of the binocular vision being
• d
• =
• fs
• μΔ
• ⁢
• ⁢
• x
• ,
• wherein μ is a physical dot pitch of the camera, f is a focal length of the camera, and s is a baseline distance between the left and right cameras;
• and
• S3003:
• obtaining, according to d=dt, a conversion formula
• Δ
• ⁢
• ⁢
• x
• =
• fs
• μ
• ⁡
• (
• α
• ⁢
• ⁢
• G
• t
• +
• β
• )
• from the grayscale value in the depth map to the binocular disparity Δx.