Translucency measurement system based on a polarized camera.

This paper proposes a measurement system capable of estimating the transmittance and haze values of a composite object. The system, comprising a polarized camera, linear polarizer, and backlight, was calibrated to obtain four phase polarization images. Forty-one samples, which covered a wide range of transmittance and haze values, were manufactured to assist in correlating the polarization images and the referenced ground truth from the BKY-Gardner instrument. After the data regression, two linear equations were selected to estimate the transmittance and haze values of transparent objects. The verification experiment for 52 samples demonstrated that the proposed method accurately estimated the transmittance of the samples with a coefficient of determination (R 2) as high as 0.96 and an average error of less than 4.1%. The haze estimation had an R 2 of 0.94 and an average error of 5.08%. Pseudo color maps were used to present the different transmittance and haze values of a single object. The proposed system can perform image-based translucency measurements and obtain individual values of a composite object.

Spatial variant gloss measurement of dielectric materials based on a polarized camera.

This study proposes an imaging method for gloss measurement solely by a single shot from a polarized camera. The system, comprising a polarized camera and well-diffused LED plate light, is inspired by the framework of ASTM D523, and it acquires images at 60° incident direction. The polarization characteristics of dielectric material samples were analyzed. A regression model was developed by using natural color system gloss scale and a commercial gloss meter. Subsequently, the gloss and spatial resolutions of this method were verified using various types of measurement samples. From experiments regarding different benchmarks, we concluded that the proposed method performs sufficiently for spatial variant gloss measurement.

Portrait imaging relighting system based on a simplified photometric stereo method.

This study proposes a portrait image relighting system based on a simplified photometric stereo method. The system, comprising a controllable digital single lens reflex camera and five polarized flashlights, can obtain a color shade-less image and synthesize a normal map from shaded images. When calibrating the photometric stereo, the normal map is taken as a linear combination of shaded images and clamped with respect to specific normal directions on a white-coated sphere. The relit images were generated through inverse rendering in a predefined virtual environment. To evaluate personal preference, 24 adult subjects were recruited to conduct subjective assessments comparing the deep portrait relighting method results. From experiments regarding different scenarios, we concluded that the proposed system based on a simplified photometric stereo performs acceptably for relighting portrait images.

Automatic 3D color shape measurement system based on a stereo camera.

This study proposes an automatic three-dimensional (3D) color shape measurement system based on images recorded by a stereo camera. The system, comprising several off-the-shelf components, is cost-effective yet capable of obtaining quality color 3D objects. In the proposed system, a turntable carrying a checkerboard is used to assist the simultaneous calibration of the stereo camera and the turntable. A slit laser is driven to swing forward and backward for generating stripes on test objects. The stereo images are collected and analyzed for obtaining matching pixels, and, consequently, the 3D point coordinates based on epipolar geometry are obtained. Screened Poisson reconstruction is utilized to integrate and smooth the scanned surfaces. With additional color images from the same camera, several multi-view texturing methods are benchmarked. We concluded that our proposed system can successfully and automatically reconstruct quality 3D color shapes of various objects.

Heliostat design for the daylighting system.

The daylighting system is designed to guide sunlight into buildings for illumination. It has the best illumination performance when sunlight vertically impinges on the collector of the daylighting system, while it has low performance when sunlight impinges obliquely. To overcome the problem, this paper investigates the design of a heliostat that reflects sunlight vertically onto a daylighting system. This study proposes a 3×3 mirror matrix heliostat, which is different from the traditional heliostat with one single mirror. With the heliostat, the system efficiency increases as high as 3.32 times.

Automatic wild bird repellent system that is based on deep-learning-based wild bird detection and integrated with a laser rotation mechanism.

Wild bird repulsion is critical in agriculture because it helps avoid agricultural food losses and mitigates the risk of avian influenza. Wild birds transmit avian influenza in poultry farms and thus cause large economic losses. In this study, we developed an automatic wild bird repellent system that is based on deep-learning-based wild bird detection and integrated with a laser rotation mechanism. When a wild bird appears at a farm, the proposed system detects the bird's position in an image captured by its detection unit and then uses a laser beam to repel the bird. The wild bird detection model of the proposed system was optimized for detecting small pixel targets, and trained through a deep learning method by using wild bird images captured at different farms. Various wild bird repulsion experiments were conducted using the proposed system at an outdoor duck farm in Yunlin, Taiwan. The statistical test results of our experimental data indicated that the proposed automatic wild bird repellent system effectively reduced the number of wild birds in the farm. The experimental results indicated that the developed system effectively repelled wild birds, with a high repulsion rate of 40.3% each day.

Fall Prevention Shoes Using Camera-Based Line-Laser Obstacle Detection System.

Fall prevention is an important issue particularly for the elderly. This paper proposes a camera-based line-laser obstacle detection system to prevent falls in the indoor environment. When obstacles are detected, the system will emit alarm messages to catch the attention of the user. Because the elderly spend a lot of their time at home, the proposed line-laser obstacle detection system is designed mainly for indoor applications. Our obstacle detection system casts a laser line, which passes through a horizontal plane and has a specific height to the ground. A camera, whose optical axis has a specific inclined angle to the plane, will observe the laser pattern to obtain the potential obstacles. Based on this configuration, the distance between the obstacles and the system can be further determined by a perspective transformation called homography. After conducting the experiments, critical parameters of the algorithms can be determined, and the detected obstacles can be classified into different levels of danger, causing the system to send different alarm messages.

Self-assembled monolayer-based selective modification on polysilicon nanobelt devices.

In this study, a self-assembled monolayer (SAM) of methoxy-poly (ethylene-glycol)-silane (mPEG-sil) was used to modify the silicon dioxide surface of polysilicon nanodevices (PNDs) to act as a passivation layer that inhibits nonspecific binding of proteins and reduces localized Joule heating power. Selective modifications of 3-aminopropyltrimethoxysilane (APTMS), NHS-biotin and dye-labeled Streptavidin on the removal regions were characterized. These PNDs, which consist of a two-level doping profile, were designed to confine heat in the low-level doping region during localized Joule heating. Localized Joule heating with pulse bias was examined in both vacuum and ambient, which indicated the removal region was longer in vacuum for the same pulse bias. Moreover, a comparison of selectively and nonselectively modified PNDs observed in time-lapsed fluorescence detection of dye-labeled Streptavidin showed a higher increasing rate in fluorescence intensity (∼2× enhancement) in the selectively modified PNDs. Finally, a COMSOL simulation was employed to evaluate the temperature distribution in the PNDs, with results showing that heat confinement was observed in the low-level doping region and a temperature very close to 673 K was achieved while applying a pulse voltage (40 V, 5 µs) to remove mPEG-sil.