Bar code image exposure judgment system and method based on CMOS

Abstract

The invention relates to a bar code image exposure judgment system and method based on a CMOS. An exposure parameter template is established, and according to sensitometric characteristics, measurement statistics is carried out on a relationship between image brightness output on the CMOS and a digital gain, an analog gain and an exposure value. The numerical relationship between the brightness output and the digital gain, the analog gain and the exposure value is qualitatively analyzed, and by initial quantities and variables of such three exposure parameters, a parameter calculation formula is established. Iterative conversion calculation is sequentially carried out to carry out N times of regulation so as to rapidly achieve expected image brightness. The method effectively solves the problem that in the prior art, exposure control (a fixed exposure gain and exposure value compensation) is carried out by a fixed step length, so that in a case that a moving object rapidly moves or environment light is suddenly dark and suddenly bright, light intensity variation is large and an image cannot be rapidly exposed to obtain rich details. By related indexes such as foreground brightness, background brightness, a contrast ratio and the like, image quality is scored so as to effectively guarantee to regulate accuracy and practicality of generated exposure parameters.

Description

technical field [0001] The invention relates to a CMOS exposure parameter control system and method, in particular to a CMOS-based barcode image exposure adjustment system and method. Background technique [0002] Barcodes include one-dimensional barcodes and two-dimensional barcodes. Due to their advantages of easy error correction, large carrying information capacity, and low production costs, they are widely used in automatic identification fields such as industrial process control, warehousing logistics, and postal management. In these process management, it is of great practical significance to improve work efficiency by quickly and successfully identifying barcodes. Since the two-dimensional code is not suitable for reading by the traditional laser scanning method, the image of the barcode is generally captured by a CMOS image sensor and then analyzed. [0003] In the prior art, when the CMOS image sensor is used for shooting, the progressive exposure control method i...

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Problems solved by technology

[0005] For this reason, the technical problem to be solved by the present invention is that in the prior art, when the light environment of the high-speed moving barcode changes, the exposure of the acquired barcode image is abnormal, which affects the subsequent barcode decoding.

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