AN IHS-BASED ENHANCEMENT METHOD WITH IMPROVED SCALE/SHIFT PARAMETER OF LINEAR MODEL

Zhang Bingxian

doi:10.5194/isprsannals-iii-3-395-2016

Abstract

An IHS-based enhancement method for colour images (IEM) is presented in this paper. An improved gamma transformation was applied to enhance the brightness and texture details of colour images taken in dark conditions. Moreover, a spatial filter was used to prevent the loss of details of highlighted areas. The method was tested with the images from the database of Simon Fraser University (SFU) and from the Chinese ZIYUAN-02C satellite. The experimental results show our proposed method could effectively enhance the luminance and texture of the images, especially for those taken in dim conditions, and maintain the hue and saturation of original images.

Highlights

Remote sensing images have played an important role in many applications, such as objective detection and image interpretation
The colour appearance of an object is believed to be determined by the surface reflectance function of surrounding objects, which is not related to the intensity of light [7]
To cope with the problem mentioned above, a linear transformation method (LTM) was proposed, which proved that linear transformation does not change the hue of images in the Intensity-HueSaturation (IHS) colour space, and the variation of saturation is decided by the scale parameter and shift parameter of linear transformation [13]

Summary

INTRODUCTION

Remote sensing images have played an important role in many applications, such as objective detection and image interpretation. Both dynamic range compression and tonal rendition are achieved by the MSR method; the method causes gray-world violation in the rendition of scenes [10] To resolve this problem, a multi-scale retinex method with colour restoration (MSRCR) [11, 12] was proposed. A multi-scale retinex method with colour restoration (MSRCR) [11, 12] was proposed All of these algorithms could improve the colour constancy to some extent, the hue of images may be changed as they mix the colour information with illumination [13]. To cope with the problem mentioned above, a linear transformation method (LTM) was proposed, which proved that linear transformation does not change the hue of images in the Intensity-HueSaturation (IHS) colour space, and the variation of saturation is decided by the scale parameter and shift parameter of linear transformation [13]. The shift parameter is changed slightly to further optimize the enhancement image quality

METHOD

LTM method

Determination of scale parameter and shift parameter

Findings

CONCLUSION