Haobo Cheng

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We propose a universal calculation formula of Fourier transform profilometry and give a strict theoretical analysis about the phase-height mapping relation. As the request on the experimental setup of the universal calculation formula is unconfined, the projector and the camera can be located arbitrarily to get better fringe information, which makes the(More)
To obtain removal functions (RFs) with high removal rate and stability in the polishing of silicon carbide mirror, an optical fabrication technology based on fixed abrasive diamond pellets (FADPs) is adopted. In this paper, we focus on the removal characteristics of FADPs, including removal profile, removal rate, stability of RFs, and surface roughness.(More)
The optimization of dwell time is an important procedure in deterministic subaperture polishing. We present a modified optimization model of dwell time by iterative and numerical method, assisted by extended surface forms and tool paths for suppressing the edge effect. Compared with discrete convolution and linear equation models, the proposed model has(More)
This study presents a subaperture stitching method to calibrate system errors of several ∼2  m large scale 3D profile measurement instruments (PMIs). The calibration process was carried out by measuring a Φ460  mm standard flat sample multiple times at different sites of the PMI with a length gauge; then the subaperture data were stitched together using a(More)
This paper presents a shadow measuring method applicable to quantitatively assessing the local deformation of aspherical mirrors. The method calls for placing an image capture setup behind the traditional knife-edge testing device to record the resultant shadow maps. Local deformation of the surface of the work-piece under testing are then extracted from(More)
The subsurface damages (SSD) of fused silica developed during deterministic small tool polishing are experimentally investigated in this study. A leather pad (i.e., poromeric) is validated to be nearly SSD-free and superior to pitch and polyurethane. Rough abrasives are found to obviously increase SSD depth, and a leather pad can efficiently suppress the(More)
Aspheric surfaces are widely used because of their desirable characteristics. Such a surface can obtain nearly perfect imaging quality with fewer optical elements and reduce the size and mass of optical systems. Various machine systems have been developed based on modern deterministic polishing technologies for large aperture aspheric surfaces. Several(More)
Minimizing subsurface damage (SSD) is in high demand for optics during grinding, lapping, and polishing. A fixed-abrasive diamond pellet (FADP) has been validated as a potential tool in fast lapping and polishing of hard optical materials. This study inspects and measures the SSD of fused silica developed in lapping and microlapping by FADPs tool through a(More)
The velocity-varying regime used in deterministic subaperture polishing employs a time-invariant tool influence function (TIF) to figure localized surface errors by varying the transverse velocities of polishing tools. Desired transverse velocities have to be truncated if they exceed the maximal velocity of computer numerical control (CNC) machines, which(More)
The influence from the ripple error to the high imaging quality is effectively reduced by restraining the ripple height. A method based on the process parameters and the surface error distribution is designed to suppress the ripple height in this paper. The generating mechanism of the ripple error is analyzed by polishing theory with uniform removal(More)