Data Compression for Image Sensor Arrays Using a 15-bit Two-Step Sigma-Delta ADC

This paper reports a readout integrated circuit with embedded data compression function for image sensors. Data compression is realized by adding a comparator in a two-step incremental sigma-delta analog-to-digital converter (ADC) with a fully floating double sampling integrator. The output differen...

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Bibliographic Details
Published in:IEEE sensors journal Vol. 14; no. 9; pp. 2989 - 2998
Main Authors: Yue, Mengyun, Wu, Dong, Wang, Zheyao
Format: Journal Article
Language:English
Published: New York IEEE 01.09.2014
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects:
Clocks
Data compression
Image coding
Image sensors
Sensor arrays
Sigma-delta modulation
Image redundancy
compressed sensing
fully-floating integrator
Sigma - Delta ADC
ISSN:1530-437X, 1558-1748
Online Access:Get full text
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Summary:This paper reports a readout integrated circuit with embedded data compression function for image sensors. Data compression is realized by adding a comparator in a two-step incremental sigma-delta analog-to-digital converter (ADC) with a fully floating double sampling integrator. The output difference between two adjacent pixels is compared with a predefined threshold using the comparator to detect redundant pixels. Once the difference is smaller than the threshold, indicating a redundant pixel, the AD conversion is omitted and the redundant information is stored using a Boolean variable. Thus, the conversion speed can be improved and the storage space is saved. An ADC test vehicle with an \(8 \times 8\) array has been fabricated using 0.5-\(\mu \) m CMOS technology. Measurement results show that the frame rate of the image sensor is 10%-236% faster than conventional ADC, and data compression ratios between 1 and 5 are achieved for images with different redundancy. The advantages of this on-chip image compression are the embedded and simple circuits, considerable speed and storage space improvement, and low power consumption. The preliminary results have demonstrated the feasibility and the effectiveness of the proposed compression method.
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content type line 14
ISSN:1530-437X
1558-1748
DOI:10.1109/JSEN.2014.2321166