Coaxial Camera Light Source Pulse Timing for Intrinsic Color Capture
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Solution Overview
Problem
Photographers face challenges in capturing intrinsic color images due to interference from external light sources, which can alter the perceived colors of subjects.
Innovation Solution
A camera system with a coaxial light source that emits a short pulse of light, allowing the image sensor to capture reflected light without external interference, using a light filter and distance determination device to minimize extrinsic light effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coaxial light source emits a pulse of light with duration shorter than the light travel time to the subject, then external light interference is eliminated and intrinsic color is captured, but the device complexity increases due to precise timing requirements and additional components
Solution Approach 1:
The light source emits light in periodic pulses rather than continuous illumination. The pulse duration is precisely controlled to be shorter than the light travel time to the subject and back, creating distinct illumination windows that eliminate external light interference while maintaining a relatively simple device architecture
Solution Approach 2:
A time delay mechanism acts as an intermediary between the light source and the image sensor. This mediator controls the timing of light emission and sensor exposure, ensuring that the sensor only captures light during the controlled pulse windows when external interference is absent, without requiring complex hardware modifications
2Reliability
If the light source is positioned coaxial with the image sensor, then the light path is optimized and external light interference is minimized, but the manufacturing precision requirements increase for aligning the light source with the optical axis
Solution Approach 1:
The light source is merged with the camera housing structure and positioned coaxial with the image sensor's optical axis. This integration ensures that the light emission path aligns with the sensor's viewing direction, optimizing the light path for capturing intrinsic color while minimizing external light interference through a single unified structure
Solution Approach 2:
The coaxial positioning of the light source with the image sensor creates a self-aligning system where the light naturally follows the optical axis defined by the lens and sensor arrangement. This self-service alignment reduces the need for complex external alignment mechanisms and minimizes manufacturing precision requirements
3Object-affected harmful factors
If a light filter is added to the lens barrel to block external light, then external light interference is reduced, but the device complexity increases and light transmission efficiency decreases
Solution Approach 1:
The harmful external light is extracted or removed from the captured light signal by using temporal separation. The system captures only the light reflected during the controlled pulse windows when external light is absent, effectively extracting the intrinsic color signal while eliminating external interference without adding physical filters that would complicate the device
4Loss of time
If the pulse width modulator is used to control the light source, then the pulse duration is precisely controlled to match the light travel time, but the device complexity increases due to additional control circuitry
Solution Approach 1:
A pulse width modulator provides feedback control for the light source emission duration. The modulator adjusts the pulse width based on the calculated light travel time to the subject, ensuring precise timing control that maximizes intrinsic color capture while minimizing external light interference through an integrated control mechanism
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 system effectively captures intrinsic color images with reduced external light interference, providing a neutral color base for relighting and accurate digital manipulation in applications like image editing and augmented reality.
Implementation Method 1
receiving a reflection of the pulse of light from the imaged subject at a lens barrel of the camera
Implementation Method 2
receiving the reflection of the pulse of light at a photosite of the image sensor to generate charge
Implementation Method 3
The lens barrel may include a light filter, the light filter including at least one of: a polarizer, a notch filter, or a waveband filter
Implementation Method 4
a polarizer
Implementation Method 5
the light source is configured to emit a pulse of light having a duration shorter than the length of time it takes to receive the reflected light from the captured subject at the lens barrel
Data Source
AI summary
Systems and methods described herein are directed to capturing intrinsic color images of subjects. A camera may be equipped with a light source that is coaxial to the camera's image sensor and configured to emit a pulse of light of short duration. During image capture of a subject, the camera light source may emit the pulse of light through the lens barrel of the camera and stop emission of light before the reflected light from the light source returns. Thereafter, the camera lens receives the reflected light from the light source (with the light source no longer emitting light) and charge is collected at one or more image sensor photodetector sites of the camera.