Ladar Range Data Video Color Rendering Using Earth-Fixed Coordinates
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Solution Overview
Problem
Existing LADAR sensor video data rendering methods cause color changes between frames, leading to undesirable visual effects when presented as video, as they do not maintain continuity of color rendering while the sensor moves.
Innovation Solution
A method using a Cartesian coordinate system fixed to the Earth and another fixed to the sensor, which computes an index for color mapping based on elevation, ensuring that pixels with similar elevations are colored consistently, preserving color continuity across frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LADAR range data is rendered using sensor-fixed coordinate system, then rendering process is simple, but color changes between frames causing visual instability
Solution Approach 1:
Instead of using the conventional sensor-fixed coordinate system that causes color changes, the patent inverts the approach by using an Earth-fixed coordinate system. This allows color to be assigned based on stable geographic elevation rather than sensor-relative position, eliminating frame-to-frame color fluctuations while maintaining rendering feasibility through coordinate transformation.
Solution Approach 2:
The patent changes the reference frame parameter from sensor-fixed to Earth-fixed coordinates. By transforming the coordinate system and using elevation (a stable Earth-referenced parameter) as the basis for color mapping, the system achieves visual stability across frames while maintaining computational efficiency through the use of an efficient approximation of the vertical axis.
2Manufacturing precision
If LADAR data is rendered for still picture, then color rendering is accurate, but color continuity is lost in video presentation
Solution Approach 1:
The patent inverts the conventional approach by rendering LADAR data in Earth-fixed coordinates rather than sensor-fixed coordinates. This allows the same color rendering accuracy achieved in still images to be maintained across video frames, as elevation-based color assignment remains consistent regardless of sensor movement between frames.
Solution Approach 2:
The patent ensures continuous color assignment across frames by using elevation as the basis for color mapping. Since elevation is a stable property of the terrain that does not change between frames, the color rendering maintains continuity throughout the video sequence, preserving both accuracy and temporal consistency.
3Stability of the object's composition
If complex coordinate transformation is used to maintain color continuity, then visual stability is achieved, but computational complexity increases
Solution Approach 1:
The patent applies partial coordinate transformation by using only the essential Earth-fixed coordinate system with an efficient approximation of the vertical axis, rather than performing complete and complex coordinate transformations. This provides sufficient visual stability for the application while significantly reducing computational complexity and processing requirements.
Data Source
AI summary
Embodiments of the invention employ a LADAR range data stream, a Cartesian coordinate system that is fixed to the Earth, and a Cartesian coordinate system that is fixed to a LADAR sensor. An index is determined and used to select a color from a color map for each range pixel of LADAR data. The color value is electronically-associated with the pixel.