An analog gamma correction scheme for high dynamic range CMOS logarithmic image sensors

Area of Science:

• Analog electronics
• Image sensor technology
• Signal processing

Background:

• High dynamic range (HDR) imaging requires careful noise management.
• Logarithmic image sensors offer wide dynamic range but can suffer from quantization noise.
• Existing gamma correction methods may increase noise or complexity.

Purpose of the Study:

• To present a novel analog gamma correction scheme for logarithmic image sensors.
• To minimize quantization noise in high dynamic range applications.
• To reduce silicon area and power consumption by integrating gamma correction with analog-to-digital conversion.

Main Methods:

• Implementation of a non-linear voltage-controlled-oscillator (VCO) based analog-to-digital converter (ADC).
• Performing gamma correction during the analog-to-digital conversion process.
• Fabrication of a test structure using a 0.35 μm standard complementary-metal-oxide-semiconductor (CMOS) process.

Main Results:

• Quantization noise does not increase.
• High dynamic range of the logarithmic image sensor is preserved.
• Significant reduction in silicon area and overall power consumption achieved.
• Validation through simulation and experimental results.

Conclusions:

• The proposed analog gamma correction scheme effectively minimizes quantization noise in HDR applications.
• Integration of gamma correction with ADC reduces hardware overhead.
• The method is suitable for advanced image sensor designs demanding low noise and power efficiency.