CV Stereo Calibrate (Chessboard)

Estimates the relative pose (R, T) between two cameras - and both sets of intrinsics unless they are pinned - from matched chessboard views (cv2.stereoCalibrate). Feed an IMAGE BATCH of stereo pairs (left and right views of the SAME board poses, same order); each pair is corner-detected independently and the matching 3-D/2-D correspondences are accumulated. Pre-calibrate each camera individually with 'Calibrate Camera' and feed BOTH K matrices here to PIN the intrinsics (CALIB_FIX_INTRINSIC - only R and T are then estimated, which is the recommended two-stage workflow); with one or neither K connected the intrinsics are estimated/refined here and any K you did pass is only an initial guess. Failure-tolerant: with fewer than 3 usable views returns found=false with identity R and zero T. Feed R, T, K, dist into 'cv2.stereoRectify' for rectification, then 'Stereo Disparity (SGBM)' for depth.