Automatic exposure method based on analogous column diagram

Abstract

The invention provides an automatic exposure method based on an analogous column diagram, which has favourable exposure effect on various situations, such as dark background light target, target size uncertainty and the like in deep space exploration. An automatic exposure control system is a closed loop control system and mainly comprises three modules: target gray level statistics, comparative judgment with expected values and exposure time calculation; data statistics analysis is carried out by gray scale region division, gray scale value weighting average calculation and the like so as to determine exposure required by shooting. Because of having low requirement on hardware, the invention can be suitable for different hardware platforms by slightly modifying, and can balance calculation speed, logic resource use, system time sequence requirement and the like according to the practical situation so as to choose different control modes.

Description

technical field [0001] The invention relates to an automatic exposure method based on a histogram-like image, in particular to an automatic exposure adjustment method for an image sensor (CCD, CMOS). In addition to conventional target environments, it can also be widely used in dark background bright targets, targets with different sizes and positions Determined detection objects (such as deep space exploration, etc.). Background technique [0002] Exposure is a physical quantity used to calculate the luminous flux from the subject to the camera. The luminous flux reaching the CCD / CMOS sensor is mainly determined by two factors: the length of the exposure time and the size of the aperture value. With a certain aperture, proper image brightness can be achieved by changing the length of the exposure time or changing the gain of the image sensor, but the change of the gain will introduce noise to the image accordingly, which complicates the subsequent processing work. The exp...

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Problems solved by technology

A method and control system for automatic exposure adjustment (China, 200510080327.5) proposes to adjust the image exposure intensity value to the target exposure intensity value range. Since the target size and shape are different under the same illuminance, the brightness of the target is also different. Therefore, this method The application has certain limitations; the method of fast automatic exposure or gain control in MOS image sensors (China, 02150634.5) proposes to count the intensity of each pixel during automatic exposure of CMOS image sensors, and adjust according to the number of pixels in a certain intensity area The corresponding exposure time, but the pixel intensity is an electrical concept, which is relatively complicated in statistics

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