Plenoptic Camera Light Emitting Device Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Calibrating a plenoptic camera is challenging due to issues with identifying the center point locations of microlens micro-images, especially with Bayer-type Color Filter Arrays, and requires frequent recalibration upon changes in the main lens settings, limiting practicality for snapshot and video applications.
Innovation Solution
Incorporating a light emitting device (LED) in the aperture stop plane of the camera lens to selectively light photosensors under each microlens, allowing for the selection of a reference pixel for demosaicing and enabling precise calibration, even during changes in lens settings or zooming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a Bayer type Color Filter Array is used on the photosensor array, then color information can be captured, but the precision of estimating microlens micro-image centers deteriorates
Solution Approach 1:
The calibration process is segmented into two independent stages: first capturing a color calibration image through the CFA to obtain color information, then capturing a grayscale calibration image without CFA interference to precisely locate micro-image centers. This segmentation eliminates the conflict between color capture and center precision.
Solution Approach 2:
A dedicated calibration mode is introduced as an intermediary process between normal color imaging and precise center estimation. This calibration mode uses a uniform illumination target and grayscale imaging to bridge the gap, providing accurate center locations that can then be applied to color image demultiplexing.
2Device complexity
If global optimization is used to estimate microlens center locations, then computational simplicity is maintained, but fabrication dispersion of individual microlenses cannot be taken into account
Solution Approach 1:
The calibration process enables the system to self-adjust for fabrication variations. By capturing actual micro-image patterns from the specific lenslet array being used, the system automatically learns and compensates for individual microlens deviations without requiring external calibration data or complex pre-characterization.
3Adaptability or versatility
If the main lens settings are changed (zooming or focalization), then adaptability is improved, but recalibration is required which reduces operational efficiency
Solution Approach 1:
The calibration parameters (micro-image center locations and dimensions) are determined in advance during a one-time initialization process. These pre-determined parameters are then stored and reused for all subsequent imaging operations, eliminating the need for recalibration when lens settings change, thus maintaining both adaptability and operational efficiency.
4Measurement precision
If frequent recalibration is performed to maintain accuracy, then measurement precision is improved, but time consumption increases
Solution Approach 1:
The calibration is performed once during system initialization or manufacturing, and the resulting parameters are stored for long-term use. This preliminary calibration action eliminates the need for repeated calibration operations, achieving both high precision and time efficiency in normal operation.
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 enhances the precision of calibrating the plenoptic camera by accurately determining the center pixel of each microlens micro-image, allowing for continuous operation without the need for frequent recalibration, even during zooming or focal changes.
Implementation Method 1
a light emitting device (LED) arranged in the aperture stop plane of the camera lens
Implementation Method 2
The microlenses 111, 112, 1n are arranged in such a way as to be optically each associated with a plurality of photosensors
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A plenoptic camera (2) comprising a camera lens (10), a lenslet array (11) comprising a plurality of microlenses (111, 112, 11n) and a photosensor array (13). In order to determine reference pixels of sub-images, the camera lens (10) comprises a light emitting device (20) arranged in the aperture stop plane of the camera lens (10), the light emitting device (20) lighting the photosensor array (13).