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Microscopic vision systems based on a stereo light microscope (SLM) are used in microscopic measuring fields. Conventional measuring methods output the disparity surface based on stereo matching methods; however, these methods require that stereo images contain sufficient distinguishing features. Moreover, matching results typically contain many mismatched points. This paper presents a novel method for disparity surface reconstruction by combining an SLM and laser measuring techniques. The surfaces of small objects are scanned by a laser fringe, and a stereo image sequence containing laser stripes is obtained. The central contours of the laser stripes are extracted, and central contours are derived for alignment. A disparity coordinate system is then defined and used to analyze the relationship between the motion direction and reference plane. Next, the method of aligning disparity contours is proposed. The results show that our method can achieve a precision of ±0.5 pixels and that the real and measured shapes described by the disparity surface are consistent based on our method. Our method is confirmed to perform much better than the conventional block-matching method. The disparity surface output obtained by our method can be used to measure the surface profiles of microscopic objects accurately.

A bio-micromanipulation system is designed for manipulating micro-objects with a length scale of tens or hundreds of microns based on stereo light microscope. The world coordinate reconstruction of points on the surface of micro-objects is an important goal for the micromanipulation. Traditional pinhole camera model is applied widely in macrocomputer vision. However, this model will output bad data with remarkable error if it is directly used to reconstruct three-dimensional world coordinates for stereo light microscope. Therefore, a novel and improved pinhole camera model applied in bio-micromanipulation system is proposed in this article. The new model is composed of binocular-pinhole model and error-correction model. The binocular-pinhole model is used to output the basic world coordinates. The error-correction model is used to correct the errors from the basic world coordinates and outputs the final high-precision world coordinates. The results show that the new model achieves a precision of 0.01 mm in the X direction, 0.01 mm in the Y direction, and 0.015 mm in the Z direction within a maximum reconstruction distance of 4.1 mm in the X direction, 2.9 mm in the Y direction, and 2.25 mm in the Z direction, and that traditional pinhole camera model achieves a lower and unsatisfactory precision of about 0.1 mm.

An electromagnetic-driven microgripper is designed for the automatic process of gripping micro-coil wire under the guidance of Stereo Light Microscope (SLM) visual system. The diameter of the wire is about 50-70 µm. Stress analyze with the ANSYS simulation software helps to obtain stress and safety factor contours of the upper and lower clamp arm when the microgripper grips wires. Simulation results show the correctness and reliability of the design. The microgripper clamping force is up to 0.9 N by theoretical calculation. Test results show that this gripper achieves a displacement of 1.1 mm. Functional test for the wire traction microgripper has been done under the guidance of SLM visual system. The wire traction microgripper is placed in three-dimensional platform, and the three-dimensional platform moves microgripper in the SLM object space close to the clamped object. Positioning accuracy error is determined by repeated positioning precision experiments on three-dimensional platform by the laser displacement sensor. Automatic process of gripping the micro-coil wire is observed and recorded in the SLM visual system to verify performance of the microgripper structure design.