Image Processing Apparatus Distance Accuracy Depth of Field
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional techniques for estimating distance information in computer vision require an increased number of focal positions, leading to longer processing times and reduced accuracy due to the influence of aperture values and distance measurement ranges, especially in applications like digital cameras, and struggle with accurately estimating distances for objects out of the optical imaging system's depth of field.
Innovation Solution
An image processing apparatus that generates a synthesized range image by combining stereo range images and depth from defocus range images using a synthesis coefficient calculated based on the depth of field of a main object, allowing for reduced focal positions and improved distance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of focal positions is increased to improve distance measurement accuracy across a wide range, then the measurement precision is improved, but the processing time increases and immediacy is reduced
Solution Approach 1:
The patent divides the depth of field into multiple segments by calculating front depth of field and rear depth of field boundaries. This segmentation allows the system to identify which segment contains the main object and select an appropriate focal position, avoiding the need to capture images at all possible focal positions. The segmentation principle resolves the contradiction by enabling accurate distance measurement with fewer focal positions.
Solution Approach 2:
The patent performs preliminary calculation of depth of field boundaries and determination of the main object's position before actual distance measurement. By pre-calculating the front and rear depth of field boundaries and identifying which segment contains the main object, the system prepares in advance to select the optimal focal position, thereby reducing processing time while maintaining measurement accuracy.
2Adaptability or versatility
If the aperture value is decreased to increase the depth of field, then the distance measurement range is extended, but the amount of change in degree of focus is reduced and measurement accuracy deteriorates
Solution Approach 1:
The patent dynamically adjusts the aperture value based on the determined focal position and the main object's location within the depth of field segments. Instead of using a fixed aperture value, the system opens the aperture wider when focusing on distant objects and narrows it when focusing on close objects. This dynamic adjustment maintains a sufficiently deep depth of field for the current focal position while preserving enough focus change for accurate measurement, resolving the contradiction between range and precision.
Solution Approach 2:
The patent changes the aperture value parameter dynamically according to the focal position and object distance. By adjusting this critical parameter based on real-time conditions rather than maintaining a fixed value, the system optimizes both the depth of field coverage and the focus change magnitude, thereby achieving accurate distance measurement across a wide range without sacrificing precision.
3Measurement precision
If multiple focal positions are used to measure objects out of the depth of field, then the measurement precision for distant objects is improved, but the device complexity and processing burden increase
Solution Approach 1:
The patent introduces depth of field boundary calculations as an intermediary step between image capture and distance measurement. By calculating the front and rear depth of field boundaries and determining which segment contains the main object, the system creates an intermediate classification that guides focal position selection. This intermediary process eliminates the need for exhaustive multi-focal-position imaging while maintaining accuracy for objects out of the depth of field, thereby reducing processing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces the number of focal positions needed for image pickup and enhances distance accuracy by effectively handling the impact of aperture values and distance measurement ranges, while ensuring accurate distance estimation for objects within and out of the depth of field.
Implementation Method 1
an imaging optical unit (101) configured to form an object image
Implementation Method 2
an image pickup unit (102) configured to pick up an object image formed by the imaging optical unit
Implementation Method 3
the depth of field of an optical imaging system of the distance measurement device 9117 is calculated by the following equations (1) to (3)
Data Source
AI summary
An image processing apparatus free from the inconvenience of an increase in the number of focal positions for image pickup or reduction of the distance accuracy. An optical imaging system forms an object image and an image pickup device picks up the formed object image. A first range image is generated from a plurality of images picked up by the image pickup device and having parallax. A second range image is generated from a plurality of images picked up by the image pickup device and having different degrees of focus at respective corresponding locations therein. A synthesis coefficient is calculated according to the depth of field of a main object selected from objects shown in the object image. A synthesized range image is generated by synthesizing the generated first range image and second range image using the calculated synthesis coefficient.