Browsing by Author "Tsai Wen-Hsiang"

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Automatic ultrasonic and computer-vision navigation device and method using the same
(2012-02-14)
Wu Chih-Jen
;
Tsai Shung-Yung
;
Tsai Wen-Hsiang
The present invention discloses an automatic ultrasonic and computer-vision navigation device and a method using the same. In the method of the present invention, the user guides an automatic navigation device to learn and plan a navigation path; next, the automatic navigation device navigates independently and uses ultrasonic signals and computer vision to detect the environment; then, the automatic navigation device compares the detected environment data with the navigation path to amend the physical movement track. The present invention enables ordinary persons to interact with the automatic navigation device without operating the computer. As the present invention adopts computer vision and ultrasonic signals to realize the functions thereof, the manufacturers can save the hardware cost.
Method for embedding secret message into PNG image
(2015-02-03)
Lee Che Wei
;
Tsai Wen-Hsiang
A method for embedding a secret message into a PNG image comprises steps: converting a secret message into a plurality of secret codes; converting the secret codes into a plurality of secret shares; using a mapping process to modify values of the secret shares to approach a full-transparent value of an alpha channel of a PNG image, and sequentially embedding the mapped secret shares into the alpha channel. As the secret shares with high-transparent values, they leave the RGB channels untouched. Thus, embedding the secret shares into the PNG image does not make difference in the appearances between the secret-carrying image and the original PNG image. Therefore, the present invention can transmit secret message securely and realize covert communication.