OpenCV Fish Eye Undistorting Issues for Object Detection

Question

I am using a fish eye lens for object detection to maximize field of view (FOV). I have code to undistort the image but the reprojection error (2.9) is not great and the edges are really messed up. I have attached some of my code and an image of the undistortion. For calibration, I took a 8 by 11 checkerboard (7x10 inner corners) and took many images in each plane.

def calibrate(showPics=True):
    # Read Image
    root = os.getcwd()
    calibrationDir = os.path.join(root,'snapshots//')
    imgPathList = glob.glob(os.path.join(calibrationDir,'*.jpg'))

    # Initialize  
    nRows = 7 
    nCols = 10
    termCriteria = (cv.TERM_CRITERIA_EPS + cv.TERM_CRITERIA_MAX_ITER,30,0.001)
    worldPtsCur = np.zeros((nRows*nCols,3), np.float32)
    worldPtsCur[:,:2] = np.mgrid[0:nRows,0:nCols].T.reshape(-1,2)
    worldPtsList = []
    imgPtsList = [] 

    # Find Corners 
    for curImgPath in imgPathList:
        imgBGR = cv.imread(curImgPath)
        imgGray = cv.cvtColor(imgBGR, cv.COLOR_BGR2GRAY)
        cornersFound, cornersOrg = cv.findChessboardCorners(imgGray,(nRows,nCols), None)

        if cornersFound == True:
            worldPtsList.append(worldPtsCur)
            cornersRefined = cv.cornerSubPix(imgGray,cornersOrg,(11,11),(-1,-1),termCriteria)
            imgPtsList.append(cornersRefined)

            if showPics: 
                cv.drawChessboardCorners(imgBGR,(nRows,nCols),cornersRefined,cornersFound)
                cv.imshow('Chessboard', imgBGR)
                cv.waitKey(500)
    cv.destroyAllWindows()

    # Calibrate 
    repError,camMatrix,distCoeff,rvecs,tvecs = cv.calibrateCamera(worldPtsList, imgPtsList, imgGray.shape[::-1],None,None)
    print('Camera Matrix:\n',camMatrix)
    print('distCoeff',distCoeff)
    print("Reproj Error (pixels): {:.4f}".format(repError))
 
    
    return camMatrix,distCoeff

def removeDistortion(camMatrix,distCoeff): 
    root = os.getcwd()
    imgPath = os.path.join(root,'snapshots//snapshot_20240310_153742.jpg')
    img = cv.imread(imgPath)
    
    height,width = img.shape[:2]
    camMatrixNew,roi = cv.getOptimalNewCameraMatrix(camMatrix,distCoeff,(width,height),1,(width,height)) 
    imgUndist = cv.undistort(img,camMatrix,distCoeff,None,camMatrixNew)

example of undistortion