Dynamic Range Assignment in Imaging Devices
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Solution Overview
Problem
Conventional image pickup apparatuses struggle with dynamic range assignment, leading to lost highlight details in bright sections and dark sections, resulting in inadequate grayscale reproduction, especially when capturing images with wide dynamic ranges.
Innovation Solution
An image pickup apparatus that synthesizes long-time exposure and short-time exposure images to generate a composite image with a wider dynamic range, dynamically varying the proportion of high luminance and low-middle luminance dynamic ranges in the output image based on the luminance region, allowing for optimal grayscale reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dynamic range assignment proportion is fixed in conventional wide dynamic range cameras, then the high luminance section detail can be preserved, but the low-middle luminance section becomes dark and loses effective dynamic range utilization
Solution Approach 1:
The patent applies dynamics by making the dynamic range assignment proportion variable rather than fixed. The control section dynamically adjusts the proportion of high luminance dynamic range to low-middle luminance dynamic range based on the actual luminance distribution in the captured image. This allows the system to adapt to different scene conditions, ensuring effective utilization of dynamic range whether the scene is predominantly bright or dark.
2Measurement precision
If back compensation weights low-middle luminance section, then shadow detail is improved, but highlight detail is lost
Solution Approach 1:
The patent applies local quality by performing different compensation operations on different luminance regions of the image. The signal processing section selectively applies back compensation to the low-middle luminance section while preserving the high luminance section details. This region-specific processing allows simultaneous optimization of both shadow and highlight detail reproduction without the trade-off inherent in global compensation approaches.
3Measurement precision
If automatic exposure adjusts for main subject, then main subject exposure is correct, but background sections suffer from lost highlight or shadow detail
Solution Approach 1:
The patent applies segmentation by dividing the image into multiple luminance regions (high luminance section and low-middle luminance section) and processing each region independently. The signal processing section performs region-specific signal processing and dynamic range assignment, allowing the main subject to receive correct exposure while background sections receive appropriate detail enhancement through selective back compensation and dynamic range allocation.
Data Source
AI summary
An image pickup apparatus for performing dynamic assignment of an output image in a dynamic range according to a subject. An image pickup device picks up an image of a subject, a signal processing section generates a composite image having a relatively wider dynamic range than at least either of the dynamic ranges of a long-time exposure image picked up with a relatively long exposure time by the image pickup device and a short-time exposure image picked up with a relatively short exposure time by the image pickup device, by synthesizing the long-time exposure image and the short-time exposure image A, control section compresses the composite image and dynamically varies the assignment proportion of a high luminance dynamic range to a low-middle luminance dynamic range in a dynamic range of an output image to be outputted as a video signal.