diff --git a/matlab/CalibratedCamera.m b/matlab/CalibratedCamera.m
new file mode 100644
index 00000000..eeea82fe
--- /dev/null
+++ b/matlab/CalibratedCamera.m
@@ -0,0 +1,30 @@
+classdef CalibratedCamera < handle
+  properties
+    ImageSize % [nr nc]
+    FocalLengths % [fx fy]
+    PrincipalPoint % [px py]
+    Skew % scalar
+    RadialDistortions % [k2 k4]
+    Rotation % [rx ry rz] rodrigues vec
+    Translation % [tx ty tz]
+  end
+  methods
+    function obj = CalibratedCamera(s)
+      for fn = fieldnames(s)', f=fn{1};
+        try
+          obj.(f) = s.(f);
+        catch
+          warning('Ignoring unrecognized field: %s', f);
+        end
+      end
+    end
+
+    function camInts = getMatlabCameraIntrinsics(obj)
+      camInts = cameraIntrinsics(...
+        obj.FocalLengths,obj.PrincipalPoint,obj.ImageSize,...
+        'Skew',obj.Skew,...
+        'RadialDistortion',obj.RadialDistortions...
+        );
+    end
+  end
+end
\ No newline at end of file
diff --git a/matlab/CameraSet.m b/matlab/CameraSet.m
new file mode 100644
index 00000000..63df8efb
--- /dev/null
+++ b/matlab/CameraSet.m
@@ -0,0 +1,59 @@
+classdef CameraSet < handle
+  properties
+    NumCameras
+    CameraNames
+    Cameras
+  end
+
+  methods 
+    function obj = CameraSet(s)
+      if ischar(s)
+        s = ReadYaml(s);
+      end
+      obj.NumCameras = s.NumCameras;
+      obj.CameraNames = s.CameraNames;
+
+      for icam=1:s.NumCameras
+        cam = s.CameraNames{icam};
+        camObjs(icam) = CalibratedCamera(s.(cam)); %#ok<AGROW> 
+      end
+      fprintf(1,'Read information for %d cameras: %s.\n',s.NumCameras, ...
+        String.cellstr2CommaSepList(s.CameraNames));
+
+      obj.Cameras = camObjs;
+    end
+
+    function [R,t] = getXformCams(obj,cam1,cam2)
+      % Get/compute matrices R,T that convert from cam1 coordsys to
+      % cam2coordsys; defined by 
+      %
+      %   [x2;y2;z2] = R*[x1;y1;z1] + t
+
+      c1 = obj.Cameras(cam1);
+      c2 = obj.Cameras(cam2);
+
+      R1 = rodrigues(c1.Rotation);
+      t1 = c1.Translation(:);
+      R2 = rodrigues(c2.Rotation);
+      t2 = c2.Translation(:);
+
+      R = R2/R1;
+      t = -R*t1 + t2;
+    end
+
+    function sp = getMatlabStereoParameters(obj)
+      if obj.NumCameras~=2
+        error('stereoParameters conversion only avaiable when NumCameras==2.');
+      end
+
+      cams = obj.Cameras;
+      sp = struct();
+      sp.CameraParameters1 = cams(1).getMatlabCameraIntrinsics;
+      sp.CameraParameters2 = cams(2).getMatlabCameraIntrinsics;
+
+      [R,t] = obj.getXformCams(1,2);
+      sp.RotationOfCamera2 = R;
+      sp.TranslationOfCamera2 = t;
+    end
+  end
+end
\ No newline at end of file
diff --git a/matlab/user/CalRigMLStro.m b/matlab/user/CalRigMLStro.m
index 27674c76..6c62788a 100644
--- a/matlab/user/CalRigMLStro.m
+++ b/matlab/user/CalRigMLStro.m
@@ -3,7 +3,8 @@
   % Note: ML Stro Calib App requires all ims/views to have the same size.
   
   properties
-    calSess % scalar Session from ML Stro calibration
+    nonMLinit = false; % if true, obj is not initialized from MATLAB stereo calibration
+    calSess % scalar Session from ML Stro calibration; or if .nonMLinit, scalar struct mirroring calSession object
     
     eplineComputeMode = 'mostaccurate'; % either 'mostaccurate' or 'fastest'
   end
@@ -62,30 +63,50 @@
   methods
     
     function obj = CalRigMLStro(calSess,varargin)
-      % calibSession: either a char filename for saved result from ML 
-      % Stereo Calib App; or the object within
+      % obj = CalRigMLStro(calSess) 
+      % calSess: one of:
+      %   1. a char filename for saved result from ML Stereo Calib App; 
+      %   2. the ML calibration Session object saved therein; 
+      %   3. char filename for APT-style rig config/param YAML file;
+      %   4. a YAML struct for such YAML contents
       
       offerSave = myparse(varargin, ...
         'offerSave',true...
         );
       
+      isYamlRig = false;
       if ischar(calSess)
-        s = load(calSess,'-mat','calibrationSession');
-        calSessObj = s.calibrationSession;
+        [~,~,ext] = fileparts(calSess);
+        switch ext
+          case '.yaml'
+            s = ReadYaml(calSess);
+            calSessObj = CalRigMLStro.rigYaml2CalSess(s);
+            isYamlRig = true;
+          case '.mat'
+            s = load(calSess,'-mat','calibrationSession');
+            calSessObj = s.calibrationSession;
+        end
       elseif isa(calSess,'vision.internal.calibration.tool.Session')
         calSessObj = calSess;
+      elseif isstruct(calSess) && isfield(calSess,'NumCameras')
+        calSessObj = CalRigMLStro.rigYaml2CalSess(calSess);
+        isYamlRig = true;
       else
         error('Input argument must be a MATLAB Stereo Calibration Session.');
       end
       
       obj.calSess = calSessObj;
+      obj.nonMLinit = isYamlRig;
       obj.int = obj.getInt();
 
       obj.eplineComputeMode = 'mostaccurate';
       %obj.autoCalibrateProj2NormFuncTol();
       obj.proj2NormFuncTol = nan; % AL20220302 no longer used
-      obj.autoCalibrateEplineZrange();
-      obj.runDiagnostics();
+
+      if ~isYamlRig
+        obj.autoCalibrateEplineZrange();
+        obj.runDiagnostics();
+      end
       
       if offerSave
         if ischar(calSess)
@@ -836,7 +857,12 @@ function rperrPlot(rperrcam1,rperrcam2)
       xp1ud = cat(1,xp1ud{:});
       xp2ud = arrayfun(@(i)undistortPoints(xp2(:,i)',cp2),(1:n)','uni',0);
       xp2ud = cat(1,xp2ud{:});
-      X1 = triangulate(xp1ud,xp2ud,sp);
+      cm1 = cameraMatrix(cp1,eye(3),[0 0 0]);
+      cm2 = cameraMatrix(cp2,sp.RotationOfCamera2,sp.TranslationOfCamera2);
+      X1 = triangulate(xp1ud,xp2ud,cm1,cm2);
+      % X1 = triangulate(...,sp); 
+      % Don't use this sig beacuse in the case of .nonMLinit, MATLAB/Vision 
+      % doesn't ducktype and requires a real stereoParameters type
       
       xp1rp = worldToImage(cp1,eye(3),[0;0;0],X1,'applyDistortion',true);
       xp2rp = worldToImage(cp2,...
@@ -904,6 +930,12 @@ function rperrPlot(rperrcam1,rperrcam2)
       alpha_c = camParams.Skew;
       assert(isscalar(alpha_c));
     end
+    function cs = rigYaml2CalSess(s)
+      % s: struct, rig yaml
+      cs = struct();
+      cs.cameraSet = CameraSet(s);
+      cs.CameraParameters = cs.cameraSet.getMatlabStereoParameters();
+    end
   end
 
 end
\ No newline at end of file