Multispectral image enhancement for effective visualization

Abstract

Color enhancement of multispectral images is useful to visualize the image's spectral features. Previously, a color enhancement method, which enhances the feature of a specified spectral band without changing the average color distribution, was proposed. However, sometimes the enhanced features are indiscernible or invisible, especially when the enhanced spectrum lies outside the visible range. In this paper, we extended the conventional method for more effective visualization of the spectral features both in visible range and non-visible range. In the proposed method, the user specifies both the spectral band for extracting the spectral feature and the color for visualization respectively, so that the spectral feature is enhanced with arbitrary color. The proposed color enhancement method was applied to different types of multispectral images where its effectiveness to visualize spectral features was verified.

Multichannel Spectral Image Enhancement for Visualizing Diabetic Retinopathy Lesions

“…The multichannel spectral image enhancement Method 1 is based on the approach introduced by Hashimoto et al [6]. In their original method, a single spectral channel i of the spectral image (a three-dimensional X × Y × N data cube containing X rows, Y columns and N spectral channels) is enhanced as follows: first, principal component analysis (PCA) is applied to the original spectral image and a spectral image estimate is calculated using m principal components (m < N) [12].…”

“…Spectral images, however, typically contain tens or hundreds of individual color channels, providing detailed color information. Furthermore, spectral image enhancement can be applied to spectral images to enhance the contrast of the wavelength-dependent properties of the object in the images [6,7,8,9,10]. Enhanced spectral images of the retina could be used for early detection of DR.…”

“…In this study, two existing methods of single-channel spectral image enhancement were modified for multichannel spectral image enhancement [6,7]. Compared to the single-channel-enhancement methods, multichannel methods allow simultaneous enhancement of different spectral features.…”

Multispectral Enhancement Method to Increase the Visual Differences of Tissue Structures in Stained Histopathology Images

“…When abnormal changes in the ratio between the cytoplasm and nuclei areas are observed other staining techniques, i.e., special stains or immunohistochemical stain, are employed to further probe the cause of the abnormality. Due to the popularity of the H&E staining, a number of investigations have been done to digitally simulate its staining effect and to investigate the discrimination of H&E stained tissue structures which are ordinarily differentiated with the use of other types of stain [2][3][4][5][6][7][8]. The success of these research endeavors would eventually allow pathologists to quantify the distribution of tissue structures in the absence of special stains.…”

“…Results on several pilot studies on the utility of multispectral imaging to improve the visualization of tissue structures and accuracy of quantitative histopathology image analysis showed promise [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. A multispectral image acquisition system captures the same scene at different spectral wavelength using narrowband spectral filters producing a stack of N grey-level spectral images, where N corresponds to the number of narrowband spectral filters employed by the imaging system.…”