Waseda University · Computer Science
Professor Sei-ichiro Kamata's research lab specializes in image processing, data compression, and spatial indexing techniques with a focus on the application of space-filling curves—particularly the Hilbert curve—in digital image and signal processing. The lab explores efficient algorithms for image scanning, lossy and lossless compression, and hierarchical image representation, emphasizing computational speed and hardware-friendly implementations. Key research directions include bit-plane decomposition, neighborhood-preserving mappings, and optimization of curve-based data organization for remote sensing and image database applications.
Figures are computed from collected data and may differ slightly.
Hyperspectral image (HSI) classification plays a crucial role in remote sensing (RS) applications, enabling the precise identification of materials and land cover based on spectral information. This supports tasks such as agricultural management and urban planning. While sequential neural models like Recurrent Neural Networks (RNNs) and Transformers have been adapted for this task, they present limitations: RNNs struggle with feature aggregation and are sensitive to noise from interfering pixels
There have been many applications of the Hilbert curve, such as image processing, image compression, computer hologram, etc. The Hilbert curve is a one-to-one mapping between N-dimensional space and one-dimensional (l-D) space which preserves point neighborhoods as much as possible. There are several algorithms for N-dimensional Hilbert scanning, such as the Butz algorithm and the Quinqueton algorithm. The Butz algorithm is a mapping function using several bit operations such as shifting, exclus
There have been many applications of Hilbert curve, such as image processing, image compression, computer holo- gram, etc. The Hilbert curve is a one-to-one mapping between -dimensional space and one-dimensional (1-D) space which preserves point neighborhoods as much as possible. There are several algorithms for -dimensional Hilbert scanning, such as the Butz algorithm and the Quinqueton algorithm. The Butz algorithm is a mapping function using several bit operations such as shifting, exclusive
Hilbert curve is one of the space-filling curves published by Peano. There are several applications using this curve such as image processing, computer hologram, etc. In this paper, we concentrate on a lossy compression technique for a gray image using the Hilbert curve. The merit of this curve is to pass through all points in a quadrant, and it always moves to the neighbor quadrant. Our method is based on this neighborhood property, by a simple segmentation of the scanned one-dimensional data u
A data compression technique using a bit-plane decomposition strategy of multivalued images is described. Although the bit-plane decomposition is mainly used for image transmission, our method takes the image expression for image database into consideration. It has two merits which are a hierarchical representation using depth-first (DF) expression and a simple noise reduction algorithm for the DF expression that is similar to human perception. The DF expression is useful for image expansion, ro
The Hilbert curve is one of space filing curves presented by G. Peano in 1890. We apply this curve to scanning an arbitrary sized image for image compression, image processing, etc. In this paper, we propose a new, simple, non-recursive algorithm for pseudo-Hilbert scanning using lookup tables. The merit of our algorithm is that the computation is fast and the hardware implementation is much easier than previous ones. From our experimental results, we have confirmed that our method is about 50 t
There have been many new developments in interactive analysis for multi-spectral images in the research of remote sensing. In general, the methods used are linear transformations such as principal component analysis. In this paper, the authors present a new interactive method for classifying multi-spectral images using a Hilbert curve which is a one-to-one mapping and preserves the neighborhood as much as possible. This method is based on a hierarchical histogram expression with different resolu
Open papers in the app to read, cite, and organize with AI.