Fixed-Point Algorithm for Infrared Sensor Temperature Conversion
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Solution Overview
Problem
Existing infrared sensor technologies face challenges in accurately converting infrared radiation to object temperature without using floating-point algorithms, which are costly and resource-intensive, and traditional fixed-point implementations lack sufficient accuracy and efficiency.
Innovation Solution
A low-cost, fast IR-to-object temperature conversion algorithm implemented in an integrated circuit chip using a microcontroller with a combination of addition, subtraction, multiplication, and shift operators that automatically establish number resolution within 32-bit registers, allowing for precise temperature conversion without tracking decimal points or exponents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If floating-point algorithms are used for IR-to-temperature conversion, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the numerical representation parameter from floating-point to fixed-point format. This allows the system to maintain adequate temperature conversion accuracy while eliminating the need for complex floating-point hardware, thereby reducing chip area and cost.
Solution Approach 2:
The patent uses a simplified fixed-point arithmetic implementation that is cheaper and more suitable for embedded infrared sensor applications. This approach sacrifices some of the precision benefits of floating-point but achieves sufficient accuracy for the application while dramatically reducing hardware requirements.
2Measurement precision
If floating-point emulation in software is used, then measurement precision is improved, but productivity decreases due to larger code size and slower execution
Solution Approach 1:
The patent changes from floating-point emulation to fixed-point arithmetic, which reduces code size and improves execution speed while maintaining adequate precision for temperature conversion applications.
Solution Approach 2:
The patent replaces the complex software-based floating-point emulation mechanism with a simpler fixed-point arithmetic approach that uses basic integer operations, thereby improving execution speed and reducing memory requirements.
3Device complexity
If traditional fixed-point implementation is used, then device complexity is reduced, but measurement precision is insufficient
Solution Approach 1:
The patent optimizes the fixed-point representation parameters and implements a specialized algorithm that achieves sufficient temperature conversion accuracy while maintaining the simplicity and low complexity of fixed-point arithmetic.
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 algorithm provides accurate temperature conversion efficiently, reducing chip area and power consumption, and is faster than floating-point emulation methods, making it suitable for low-cost infrared sensors with small chip sizes.
Implementation Method 1
A remote object which has a surface temperature Tobj emits infrared radiation (IR). An IR system includes an IR sensor which generates a digital representation Vobj of the temperature of remote object
Data Source
AI summary
A system including an integrated circuit chip also includes a microcontroller in the chip and an algorithm for execution by the microcontroller. The algorithm includes addition, subtraction, and multiplication operators (e.g. 25,15,20) and shift-left and shift-right operators (e.g., 48,21) configured for solving particular equations (Eqns. 1-4). Input numbers are within particular ranges to allow the shift operators to shift binary bits so each number so it fits within a register of a particular width. An IR sensor (4) may convert IR radiation (3) to produce a voltage (Vobj) representing the temperature (Tobj) of an IR emitting object (2). The algorithm (100) operates in conjunction with the microcontroller (7) to convert the voltage (Vobj) into a value representing the temperature (Tobj) of the remote object (2) without keeping track of decimal points and resolution of the numbers.