Cheng-Pei Tsai

A practical nighttime vehicle distance alarm system

This paper presents a practical nighttime vehicle distance measuring method based on a single CCD image. The method combines an image-based distance measuring system. To solve the nighttime feature extraction problem, the proposed method uses two taillights as the feature. Based on the proportionality of similar triangles, distance between a CCD camera and the taillights of the vehicle ahead can be measured. The method focuses on detecting the taillights and differentiating the targeted vehicle from others on the basis of partial image analysis instead of whole image processing. The system is both fast and simple. The accuracy of the proposed method is demonstrated in this paper through experiences.

A single CCD measuring method for three-dimensional rectangular objects

In this paper, a measuring system using IBDMS and PLDMS method through a CCD camera is proposed. The proposed measuring system is an easy-to-construct system to measure the three-dimensional rectangular objects by using a single CCD camera. In our proposed measuring system, the ruler for the measured objects can easily be defined by two laser points for a far distance or by a know-size and easy-to-get paper money for a near distance. For the far distance, the corrosion surface objects can be measured by ready lasers system. Otherwise, when the measured object stays in the near distance, an easy-to-get paper money can be used. Based on the known parameters, the proposed measurement can release the limitations of the photography angle. After measuring three-dimensional information, we can further to compute the volume of rectangular objects.

Image-based landslide monitoring system

A novel image-based landslide monitoring system proposed in this paper, which is using digital image processes methods to detect landslide occurred in any landslide occurred situation to achieve a non-contact landslide monitoring system by one image. The theory of this system is based on using a laser projector to project a laser beam to measurement box, which have two acrylic boards in the measurement box. When landslide occurred, the laser beam will generate two laser spots in image. To identify the coordinate of laser spots through an easy calculation, the system could get the landslide displacement and offset angle. According the measurement result, it could announce the warning and prevent the damage.

Height measuring system via slant photography

In this paper, a novel distance measuring method to measure the height of a building is proposed. Traditionally, distance measuring using CCD is based on stereo parallax. This paper puts forward a method of measuring the width and height of a building regardless of the distance of the camera or the angle between optical axis and ground. By using two parallel laser spots, the distance from the camera to the building and the height, the width of the building, and the area of special region can be determined in a single photo session and with a single picture. Experiments show that even highly non-orthogonal pictures taken from a short distance can be used to determine the height of a building. The result will not be affected by the angle between the cameras optical axis, the ground and the measured surface.

Label System on Cartesian Coordinate by Using a Digital Camera

a novel image-based label system is proposed in this paper, we can convert the coordinate in image into Cartesian coordinate by using an image from a single CCD camera. This system could correspond arbitrary two points on the image convert to the actual distance no matter the digital camera is vertical to the measuring plane or not and the height of digital camera. Here designed a new structure for reach the goal of our proposed, first of all use four laser projector. Second, generate four laser spots on a measurement plane. Then, assume connect each two laser spot as parallel lines. Now we have simulated an automatically adjusts the resolution of the measurement ruler in the image. Because theres no capture angle constraint for the camera, it can use to measure horizontally such as: area of floor, or vertically such as: height of building.

Image-based detection and obstacle avoidance for mobile robots

In this paper, we use two visible laser points as the measuring ruler for automatically adjusting measurement. It is a breakthrough compared with using double CCD cameras or the measuring method of setting up reference at measuring points. By using a single image, we can realize the non-contact distance measurement. The measuring principle is to produce two bright projection spots on the measuring surface with two parallel lasers projectors. As a result, the pixel value between the spots will change in accordance with the shooting distance. As long as the pixel value between the two bright spots in the image frame can be identified, distance measurement can be obtained for detection and obstacle avoidance for mobile robots by using a single camera image.