An improved position errors test method of image recorded by voyage data recorder

Voyage data recorder (VDR) is used to record vessels' navigation data. Image is one of the essential data recorded by VDR. According to International standard-IEC 61996, compared with the original image, the one recorded by VDR may contain color and position errors. In this paper, an improved position errors test method is proposed based on IEC 61996. An image which contains two colors, black and white, is used as the input image. By setting the threshold of grey scale, certain white pixels are detected and their coordinates are recorded. Position errors are calculated according to the white pixels' coordinates in the input and output images. Based on the proposed method and IEC 61996, an image fidelity test system is set up and an image comparison system is designed. An image with known position errors is used as the output image from VDR to assess the proposed method.