Transparent Calibration Pattern for Film Scan Light Intensity
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Solution Overview
Problem
In motion picture scanning systems, ensuring consistent light intensity across the imaging sensor from top to bottom and left to right is crucial, but existing methods lack a reliable way to verify and correct for variations, especially when dealing with films of variable density, as there are no test patterns on typical reels and including external patterns would reduce image resolution.
Innovation Solution
A transparent calibration pattern is placed in front of or behind the film, comprising lines that can be viewed through perforations, allowing for the measurement of light intensities and application of corrections, enabling accurate calibration and validation of light intensity variations across the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test pattern is included outside the edges of a reel of film, then calibration and validation of light intensity becomes possible, but resolution available to the picture image is reduced
Solution Approach 1:
The calibration pattern is nested within the existing film structure by utilizing the perforations (sprocket holes) that are already present on the film reel. The transparent calibration pattern is positioned behind the film, allowing calibration lines to be visible through the perforations without requiring additional external space, thus avoiding reduction of picture image resolution.
Solution Approach 2:
Instead of placing the calibration pattern in the horizontal plane (outside film edges), the solution moves the calibration pattern to a different dimension - positioning it behind the film in the depth dimension. This allows the calibration information to be superimposed on the existing film area without consuming additional picture image space.
2Adaptability or versatility
If light intensity is intentionally varied during the scan to suit reels with variable density sections, then suitability for variable density film is improved, but verification and validation of exposure intensity becomes difficult
Solution Approach 1:
The calibration pattern provides a reference standard that enables feedback measurement of the scanning exposure intensity. By comparing the scanned calibration pattern against known reference values, the system can verify and validate the actual exposure intensity applied, even when intentional variations are made for variable density film sections.
Solution Approach 2:
The calibration pattern uses different optical densities (analogous to color/intensity variations) to create distinguishable reference levels. These density variations in the calibration pattern allow for measurement and verification of the scanning exposure intensity across different brightness levels, enabling validation of intentional exposure variations.
3Area of stationary object
If no test pattern is included on the film reel, then picture image area is maximized, but ability to determine quality of set-up and validate scans is lost
Solution Approach 1:
A transparent calibration pattern is introduced as an intermediary element positioned behind the film. This intermediary carries the calibration information without being part of the picture image itself, allowing quality validation to occur through the existing film structure without compromising picture image area.
Solution Approach 2:
The solution utilizes the perforated structure of the film (the porous/nested structure of sprocket holes) as the carrier for calibration information. By making the calibration pattern transparent and positioning it behind the film, the calibration data can be viewed through the perforations, effectively using the existing porous structure to convey additional functional information without occupying picture image space.
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
This method allows for precise calibration and validation of light intensity, enabling the creation of an accurate map of intensity variations, correcting minor exposure changes, and providing a historical record of intentional exposure variations, ensuring consistent and high-quality digital film scans.
Implementation Method 1
a transparent calibration pattern being placed in front of or behind a film wherein a user can view the transparent calibration pattern through perforations in the film
Data Source
AI summary
There is herein described a method and apparatus for the calibration and validation of motion picture scans.