Is the extrinsic well calibrated?

[heyfluke]

I am integrating synced 4-cam image to a surrounding view system.
The left and right camera seems not calibrated well.

See equirectangular projected images:

My code is straightforward:

step 1:
generate spherical vertex in OpenGL coordinate.

step 2:
for all vertex (Pw) do cam_to_img() convertion which is 3d to 2d projection.

    glm::mat3 Tw = glm::mat3(0,0,-1,
             -1,0,0,
             0,1,0); // gl to vehicle
    glm::vec3 Pc = Tw * glm::transpose(R) * Pw + t;

    if (Pc.z < 0) {
        return glm::vec2(-1,-1);
    }
    float chi = sqrt(Pc.x*Pc.x + Pc.y*Pc.y);
    float theta = atan2(chi, Pc.z);
    float theta2 = theta*theta, theta3 = theta2*theta, theta4 = theta2*theta2;
    float rho = k1*theta + k2*theta2 + k3*theta3 + k4*theta4;
    glm::vec2 uv;
    if (chi != 0) {
        uv.x = rho * Pc.x / chi;
    } else {
        uv.x = 0.0;
    }
    if (chi != 0) {
        uv.y = rho * Pc.y / chi;
    } else {
        uv.y = 0.0;
    }
    uv.x += resolution.x/2; // roughly cx
    uv.y += resolution.y/2;
    return uv;

[heyfluke]

BTW. images are 5710 - 5713