River Drying-Up Extraction via iNDWI and MVC Remote Sensing
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Solution Overview
Problem
Existing methods for extracting river drying-up regions and frequencies using optical remote sensing satellites are time-consuming, laborious, and prone to subjective errors, and they cannot efficiently process large regions or track changes over specific periods.
Innovation Solution
A method that involves acquiring an optical remote sensing image set, preprocessing the images, computing inverse normalized difference water index (iNDWI) values, and using maximum value composite (MVC) techniques to mosaic and extract river drying-up regions, ultimately generating a drying-up frequency image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual interpretation is used to extract river drying-up regions from optical remote sensing images, then extraction accuracy can be maintained, but the process becomes time-consuming and laborious
Solution Approach 1:
The patent replaces manual visual interpretation with an automated computational method using inverse normalized difference water index (iNDWI) calculations. This substitution of mechanical/manual processes with automated image processing algorithms resolves the contradiction by maintaining extraction accuracy through systematic computational approaches while dramatically reducing processing time and labor requirements.
Solution Approach 2:
The patent transforms the extraction process by changing from subjective visual assessment to objective quantitative parameter analysis using iNDWI values. By establishing threshold-based classification systems and using composite indices derived from remote sensing data, the method maintains scientific rigor and accuracy while enabling automated, efficient processing of large datasets.
2Measurement precision
If visual interpretation is used for river drying-up extraction, then detailed analysis can be performed, but it cannot be applied to large regions
Solution Approach 1:
The patent creates a universal extraction methodology that can be applied across diverse spatial scales and regional contexts. The iNDWI-based approach combined with maximum value composite (MVC) techniques provides a standardized framework that maintains extraction quality whether applied to small local areas or large regional studies, enabling the method to serve multiple spatial scales simultaneously.
Solution Approach 2:
The patent processes large spatial regions by dividing remote sensing images into manageable processing units or tiles. This segmentation allows the automated extraction method to handle extensive geographic areas systematically, maintaining consistent extraction quality across the entire region while enabling parallel processing to further reduce computation time.
3Productivity
If single time point images are processed, then processing speed is maintained, but river drying-up regions and frequencies over specific periods cannot be identified
Solution Approach 1:
The patent performs preliminary processing of multiple temporal images by computing iNDWI values and creating maximum value composite images before final extraction. This preliminary action on individual time points enables subsequent analysis of temporal patterns and frequency calculations, preserving temporal change information while maintaining processing efficiency through staged computational approaches.
Solution Approach 2:
The patent merges information from multiple time points by creating maximum value composite images that integrate data across the study period. This combining approach preserves temporal dynamics and enables frequency analysis while allowing efficient batch processing of multi-temporal datasets, thus maintaining productivity without losing temporal information.
4Productivity
If automated methods are used to reduce processing time, then efficiency increases, but subjective factors cannot be completely eliminated
Solution Approach 1:
The patent transforms subjective visual interpretation into objective quantitative analysis by using standardized remote sensing indices (iNDWI) with defined calculation formulas and threshold values. This parameter-based approach ensures consistent, reproducible results that are free from human subjectivity while maintaining high processing efficiency through automated computation.
Solution Approach 2:
The patent incorporates validation mechanisms and quality control steps that provide feedback on extraction results. By comparing automated extraction outcomes with expected patterns and using iterative refinement processes, the method ensures reliability and objectivity while maintaining computational efficiency through automated feedback loops rather than manual review.
Data Source
AI summary
The present disclosure provides a method, apparatus, medium and device for extracting a river drying-up region and frequency, and belongs to the technical field of remote sensing. The method for extracting a river drying-up region and frequency can be applied to efficiently acquiring river drying-up information for a long time within the large spatial region. With the inverse normalized difference water index (iNDWI) and the maximum value composite (MVC) method for the remote sensing images, the present disclosure omits the troublesome step of separately extracting a river range for each image in the conventional method. In addition, the present disclosure quickly obtains the drying-up frequency by counting the total number of available images and the number of non-water images at the same pixel position, and yields a greater efficiency for extracting the river drying-up region and frequency.