Computing reflectance ratios from an image

نویسندگان

  • Shree K. Nayar
  • Ruud M. Bolle
چکیده

This paper presents a photometric invariant called reeectance ratio that can be computed from a single brightness image of a scene. The brightness variation in an image of a surface depends on several factors; the three-dimensional shape of the surface, its reeectance properties, and the illumination conditions. Since neighboring points on a smoothly curved surface have similar surface orientations, their brightness values can be used to compute the ratio of their reeectance coeecients. Based on this observation, we develop an algorithm that estimates a reeectance ratio for each region in the image with respect to its background. The algorithm is computationally eecient as it computes ratios for all image regions in just two raster scans. In the rst scan, the image is segmented into regions using a sequential labeling algorithm. During labeling, the reeectance ratio between adjacent pixels is used as a measure of connectivity. In the second scan, a reeectance ratio is computed for each image region as an average of the ratios computed for all points that lie on its boundary. The region reeectance ratio is also a photometric invariant; it represents a physical property of the region and is invariant to the illumination conditions. Several experimental results are included to demonstrate the invariance of reeectance ratios to imaging and illumination parameters. We conclude with a brief discussion on the application of reeectance ratios to the problems of object recognition and visual inspection.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Image Enhancement via Reducing Impairment Effects on Image Components

In this paper, a new approach is presented for improving image quality. It provides a new outlook on how to apply the enhancment methods on images. Image enhancement techniques may deal with the  illumination, resolution, or distribution of pixels values. Issues such as the illumination of the scene and reflectance of objects affect on image captures. Generally, the pixels value of an image is ...

متن کامل

ارائۀ ساده‌ترین نسبت‌های طیفی به‌منظور تشخیص برخی خصوصیات شیمیایی خاک در مناطق خشک با استفاده از تکنیک دورسنجی (مطالعۀ موردی: کویر درۀ انجیر بافق)

Introduction Understanding the spectral reflectance of different soils and other surface elements forms the basis for analyzing the process of interpreting remote sensing data. Spectral properties of the various phenomena of the Earth's surface are not constant and are changing, based on the complex time and space conditions. Determination of soil chemical properties using remote sensing techni...

متن کامل

Computing of the Burnt Forest Regions Area Using Digital Image Processing

At present, there is no conventional scientific method to evaluate the area of the burnt regions of forests and in this field, the related organizations use different methods and variables. Also, the speed in performing the processes of area computing and damage evaluation, especially in the extensive damaged forest regions is very slow; consequently, the expression of results takes more ti...

متن کامل

Computing of the Burnt Forest Regions Area Using Digital Image Processing

At present, there is no conventional scientific method to evaluate the area of the burnt regions of forests and in this field, the related organizations use different methods and variables. Also, the speed in performing the processes of area computing and damage evaluation, especially in the extensive damaged forest regions is very slow; consequently, the expression of results takes more ti...

متن کامل

Implementation of VlSI Based Image Compression Approach on Reconfigurable Computing System - A Survey

Image data require huge amounts of disk space and large bandwidths for transmission. Hence, imagecompression is necessary to reduce the amount of data required to represent a digital image. Thereforean efficient technique for image compression is highly pushed to demand. Although, lots of compressiontechniques are available, but the technique which is faster, memory efficient and simple, surely...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Pattern Recognition

دوره 26  شماره 

صفحات  -

تاریخ انتشار 1993