Multi-grade backlight detection method and device

Abstract

The invention provides a multi-grade backlight detection method and a device. The multi-grade backlight detection method comprises the steps of S101, blocking a target image and acquiring a brightness value of each image block; S102, carrying out detail analysis on the image blocks and converting the brightness value of each image block into a brightness evaluation value of the image block according to a brightness score mapping table; S103, synthesizing the evaluation values of all image blocks so as to acquire the backlighting degree of the whole image; and S104, guiding exposure selection according to the backlighting degree so as to provide an appropriate image for HDR synthesis. According to the invention, backlighting scenes, overexposure/underexposure areas and the degrees thereof are accurately differentiated, and the backlighting degree of the image is evaluated; exposure selection is guided according to the backlighting degree of the current image, appropriate exposure enables image details to be richer, and an image with high quality can be acquired through HDR synthesis.

Description

technical field [0001] Embodiments of the present invention relate to a backlight detection method and device, in particular to a multi-stage backlight detection method and device. Background technique [0002] Portable mobile devices have become an indispensable part of people's daily life. With the increasing development of portable mobile devices, mobile devices with shooting functions are becoming more and more perfect. Now people travel and play, and rarely use digital cameras or simple cameras. More people choose mobile devices with shooting functions. However, due to the limited gray scale of imaging devices such as digital cameras and mobile phones, when shooting scenes with wide brightness distribution, local overexposure and underexposure usually occur, which affects the image quality. The backlight detection in the prior art can analyze the scene to determine whether there is backlight, but it cannot provide guiding suggestions for exposure, etc., and cannot fund...

AI Technical Summary

Problems solved by technology

However, due to the limited gray scale of imaging equipment such as digital cameras and mobile phones, when shooting scenes with wide brightness distribution, local overexposure and underexposure usually occur, which affects the image quality

The backlight detection in the prior art can analyze the scene to determine whether there is backlight, but it cannot provide guiding suggestions for exposure, etc., and cannot fundamentally improve the imaging quality

[0003] Patent Publication No. CN 103916603 A proposes to determine the dark area and bright area in the image to be detected according to the brightness relationship between the adjacent image blocks, and determine the area to be detected according to the dark area and bright area. Whether the image is a backlight scene; Patent Publication No. CN 105049743 A proposes to determine the backlight according to the brightness value distribution, the ratio of different brightness intervals, and the preset threshold by obtaining the total number of pixels and the brightness value distribution of the pixels in the image of the object to be photographed Scene detection; Patent Publication No. CN 105227843 A proposes to detect the current ambient brightness through the light sensor of the terminal, and when the current ambient brightness is greater than the threshold value, judge whether it is backlighting according to the brightness histogram; the above patented technology can distinguish backlighting and non-backlighting to a certain extent scene, but it cannot accurately distinguish the degree of backlight, and cannot effectively improve the image quality

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