Koichiro Deguchi

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This paper considers the problem of factorizing a matrix with missing components into a product of two smaller matrices, also known as principal component analysis with missing data (PCAMD). The Wiberg algorithm is a numerical algorithm developed for the problem in the community of applied mathematics. We argue that the algorithm has not been correctly(More)
This paper examines numerical algorithms for factorization of a low-rank matrix with missing components. We first propose a new method that incorporates a damping factor into the Wiberg method to solve the problem. The new method is characterized by the way it constrains the ambiguity of the matrix factorization, which helps improve both the global(More)
A general scheme to represent the relation between dynamic images and camera and/or object motions is proposed for applications to visual control of robots. We consider the case where a moving camera observes moving objects in a static scene. The camera obtains images of the objects moving within the scene. Then, the possible combinations of the camera and(More)
Maximum likelihood (ML) estimation is widely used in many computer vision problems involving the estimation of geometric parameters, from conic fitting to bundle adjustment for structure and motion. This paper presents a detailed discussion on the bias of ML estimates derived for these problems. Statistical theory states that although ML estimates attain(More)
This paper is concerned with photometric methods using three images with different lighting direction to obtain shape information of an object. Such methods are based on the photometric equation that relates the normal of the object surface to the triplet of the image brightness. This paper discusses the issue of whether the surface normal and the(More)