Image Inspection Apparatus Using Pre-Calculated Correction Parameters
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Solution Overview
Problem
Existing image inspection systems are inefficient in correcting for positional shifts in printed images due to non-stationary noise, leading to increased processing time and computation loads as the image forming apparatus operates over time.
Innovation Solution
The system corrects one of the currently read image or the master image using a previously calculated correction parameter before comparison, ensuring that pixel positions match to efficiently remove positional shifts attributable to non-stationary noise, thereby improving inspection accuracy and reducing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pattern matching is used to correct positional shift in read image, then inspection accuracy is improved, but processing time and computation load increase
Solution Approach 1:
The patent applies preliminary action by calculating correction parameters for stationary noise in advance and storing them. These pre-calculated parameters are then reused for multiple read images, avoiding repeated complex pattern matching operations. This resolves the contradiction by performing the computationally intensive work beforehand, thus maintaining high inspection accuracy while significantly reducing processing time for each individual image inspection.
2Measurement precision
If pattern matching is used to correct positional shift, then inspection accuracy is improved, but computation load increases
Solution Approach 1:
The system performs the computationally intensive pattern matching operation only once to calculate correction parameters for stationary noise. These parameters are then stored and reused for subsequent images, dramatically reducing the computation load for each inspection while maintaining the accuracy benefits of pattern matching-based correction.
Solution Approach 2:
The patent creates a copy of the correction parameters derived from pattern matching and reuses this copied information for multiple images. Instead of performing pattern matching on every image, the system copies the correction methodology and applies it repeatedly, reducing computation load while preserving inspection accuracy.
3Loss of time
If correction parameter from previously read image is used, then processing time is reduced, but accuracy in correcting non-stationary noise deteriorates
Solution Approach 1:
The patent separates the correction process into two parts: stationary noise correction parameters are calculated in advance and stored, while non-stationary noise is handled by applying these pre-calculated parameters to each new read image. This preliminary calculation approach reduces processing time while the parameters are designed to account for temporal changes in print processing conditions.
Solution Approach 2:
The system adjusts correction parameters based on changes in print processing conditions over time. By monitoring temporal variations and updating the pre-calculated correction parameters accordingly, the system maintains accuracy for non-stationary noise while preserving the time-saving benefits of using pre-computed parameters.
Data Source
AI summary
An inspection apparatus obtains a correction parameter for correcting the positional shift between a previously read image and a master image, and corrects one of a currently read image or a master image using the correction parameter for the previously read image, before comparing between the currently read image and the master image to detect the positional shift in the currently read image.