Motion-blur-free video shooting system based on frame-by-frame intermittent tracking

ROBOMECH Journal, Dec 2017

In this paper, a concept of frame-by-frame intermittent tracking to achieve motion-blur-free and high-brightness images when video shooting fast moving scenes is proposed. In our tracking concept, two control methods are applied alternately at hundreds of hertz, according to the open or closed shutter state of the camera. When the shutter is open, the target’s speed in images is controlled at zero and visual feedback is transmitted to achieve motion blur reduction, and when the shutter is closed, the camera returns to its home position. We developed a prototype of our motion-blur-free video shooting system, which consists of our tracking method implemented on a high-speed two degrees-of-freedom tracking vision platform that controls the pan and tilt directions of the camera view by using high-speed video processing in order to reduce motion blur. Our motion-blur-free video shooting system can capture gray-level $$512\times 512$$ 512 × 512 images at 125 fps with frame-by-frame intermittent tracking. Its performance is verified by the experimental results for several video sequences of fast moving objects. In the experiments, without a decrease in the exposure times our method reduced image degradation caused by motion blur.

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Motion-blur-free video shooting system based on frame-by-frame intermittent tracking

Inoue et al. Robomech J Motion-blur-free video shooting system based on frame-by-frame intermittent tracking Michiaki Inoue 0 Mingjun Jiang 0 Yuji Matsumoto 0 Takeshi Takaki 0 Idaku Ishii 0 0 Department of System Cybernetics, Hiroshima University , Higashi-Hiroshima , Japan In this paper, a concept of frame-by-frame intermittent tracking to achieve motion-blur-free and high-brightness images when video shooting fast moving scenes is proposed. In our tracking concept, two control methods are applied alternately at hundreds of hertz, according to the open or closed shutter state of the camera. When the shutter is open, the target's speed in images is controlled at zero and visual feedback is transmitted to achieve motion blur reduction, and when the shutter is closed, the camera returns to its home position. We developed a prototype of our motion-blur-free video shooting system, which consists of our tracking method implemented on a high-speed two degrees-of-freedom tracking vision platform that controls the pan and tilt directions of the camera view by using high-speed video processing in order to reduce motion blur. Our motion-blur-free video shooting system can capture gray-level 512 × 512 images at 125 fps with frame-by-frame intermittent tracking. Its performance is verified by the experimental results for several video sequences of fast moving objects. In the experiments, without a decrease in the exposure times our method reduced image degradation caused by motion blur. Target tracking; High-speed vision; Active vision; Motion deblurring Introduction Motion blur is a well-known phenomenon that occurs when shooting images of fast moving scenes. The degradation degree of images caused by motion blur depends on the duration of the camera exposure, as well as on the apparent speed of the target scenes, and the camera’s exposure time is often decreased in order to reduce motion blur. However, a trade-off exists between brightness and motion blur in image shooting, because it is difficult to obtain non-blurred bright images with a decreased exposure time, since less light is then projected onto the image sensor. This trade-off is extremely aggravated in highly magnified observations of fast moving scenes in various application fields, such as flowing cells in microscopic fields, precise inspection of products on a moving conveyor line, and road surface and tunnel wall inspection from a moving car, because the apparent speed of the scene increases in the magnified camera view and the light that is projected on the image sensor diminishes when the magnification is increased. Motion deblurring is a frequently used approach for reducing this image degradation resulting from motion blur in image shooting. In many studies, approaches [ 1, 2 ] were developed that apply blur kernels that express motion blur in the input images; the blurred images are restored by deconvolving the images with the estimated blur kernels. These approaches include single-image deblurring methods [ 3–5 ] and multi-image deblurring methods [ 6–8 ]. In the former, the blur kernels are estimated from a single image using parametric models for maximum a-posteriori estimation and in the latter the illposed problems in deconvolution are reduced by estimating the blur kernels from multiple images. Several papers have reported motion deblurring methods that consider the camera’s egomotion while the shutter is open, which is estimated by using gyro sensors and accelerometers [9] or the camera’s geometric location [ 10 ]. However, most of these methods adopt a software-based approach for image restoration and do not consider the acquisition of blur-free input images. There are limitations to the extent to which images can be improved, in particular when significant changes in the target scene occur in the images captured while the camera shutter is open. To reduce motion blur resulting from camera shake, a large number of digital cameras with camera-shake reduction systems have been developed that can stabilize input images by shifting their optical systems mechanically. These image stabilization systems are categorized into two types according to the approach that is applied: the lens-shift approach, which shifts a floating lens to move the optical axis [ 11, 12 ] and the sensorshift approach, which shifts the image sensor [13]. These image stabilizers can stabilize input images by controlling the optical path with a floating lens or the position of the image sensor with the camera’s internal sensors, such as its gyro sensor. The camera-shake reduction system is a camera-stabilization approach that uses the camera internal sensors for reducing motion blur resulting from camera shake; it is unsuitable for shooting blur-free images of fast moving scenes when the camera is fixed, because the internal sensors cannot detect any apparent motion in the captured images. Many high-speed vision systems operating at 1000 fps or more have b (...truncated)


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Michiaki Inoue, Mingjun Jiang, Yuji Matsumoto, Takeshi Takaki, Idaku Ishii. Motion-blur-free video shooting system based on frame-by-frame intermittent tracking, ROBOMECH Journal, pp. 28,