共查询到20条相似文献,搜索用时 171 毫秒
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基于极大灰度频数抑制结合动态直方图均衡的图像增强算法 总被引:3,自引:0,他引:3
现有的直方图均衡技术存在两方面不足:虽然使得增强图像有高的对比度,但是其对比度的提升程度严重依赖于灰度频数分布,这样常常导致容易过度增强高频数灰度级,而压缩低频数灰度级;另外,增强对象缺乏目的性,难以满足感兴趣灰度区域的特殊要求。针对这个问题,该文提出基于极大灰度频数抑制结合动态直方图均衡的图像增强算法。首先通过分析图像直方图的灰度分布情况来分割图像,并根据用户感兴趣灰度范围确定各子层图像的灰度映射范围及频数控制阈值;然后利用各自阈值重新定义子层直方图,并采用直方图均衡算法构造灰度转换函数,将子层灰度映射到指定范围内;最后综合各个子层的增强结果得到最后的增强图像。实验结果表明,该算法既能抑制过度增强的情况,又能对于用户感兴趣的灰度进行控制,能更好地满足用户对图像对比度增强可控的应用要求。 相似文献
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针对红外图像普遍存在目标与背景对比度差、边缘模糊、信噪比低和灰度层次差等缺陷,提出了一种改进的直方图均衡红外图像增强算法。首先通过自适应地选择合适的灰度阈值,在图像直方图中将像素所占比例小于阈值的冗余灰度级完全压缩,并对大于阈值的有效灰度级进行基于一种非常合理的对数函数的拉伸变换;然后对拉伸后的灰度级进行常规的直方图均衡处理;最后在整个灰度范围内对经过均衡处理的图像灰度级进行等间距排列。为了满足算法的实时性,设计了一种以TMS320DM642高性能DSP芯片为核心处理器的红外图像增强系统平台。实验结果表明,采用该算法增强后的图像质量明显优于采用直方图均衡算法增强后的图像质量,图像的目标与背景的对比度和图像的清晰度都得到了提高,边缘细节也得到了保留;同时,采用该算法处理一帧320×256×8bits的红外图像仅仅用时16.73ms,完全满足实时图像处理的要求。 相似文献
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一种自适应红外舰船图像增强算法 总被引:3,自引:0,他引:3
复杂环境下海面舰船红外图像信噪比和对比度低、边缘模糊,目前仍没有一种处理效果好且实时性强的图像增强算法。提出一种基于平台直方图均衡化的自适应红外图像增强算法。首先,分析典型海面舰船红外图像及其直方图的特性;在此基础上,提出一种自适应确定目标/背景粗略阈值的方法;最后将灰度大于该阈值的直方图最大值作为平台值,通过平台直方图均衡化算法自适应地完成海面舰船红外图像的图像增强。实验结果表明,该算法不但有效地增强了图像的对比度、抑制了背景,而且具有较快的运算速度。 相似文献
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针对不同场景水下退化图像出现的颜色失真和低 对比度等问题,提出了一种联合多通 道均衡与多尺度融合的水下图像增强方法。首先利用绿通道补偿红通道并通过区域红通道 均值二次加强红通道,其次利用自适应平台直方图均衡扩展R、G、B 3通道灰度级范围并 重新分配灰度值,最后将经过Gamma 、GUM 和CLAHE 算法处理的亮度V(Value )分量进 行多尺度融合。实验结果表明,本文算法简单而有效,能够明显改善图像雾化现象和蓝绿 外观,增强图像清晰度,且在多种场景下均表现出较强的泛化适应能力。 相似文献
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针对红外图像对比度增强的问题,提出了一种新方法。首先对直方图去冗余与灰度线性拉伸,然后利用最小误差阈值法将图像分割成两部分,结合平台直方图与双直方图均衡化,在每部分单独使用平台直方图均衡化。为了提升算法的自适应性,对分割后各部分进行直方图对数变换代替平台阈值的选取。实验表明,该算法效果较好,且完全自适应,适用于多种红外图像。 相似文献
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Histogram equalization is the common method used for contrast enhancement. The mean brightness of the image is adjusted to middle of the permitted range and hence is not suitable for consumer electronics products. A novel contrast enhancement method using modified octagon histogram equalization is developed to overcome the drawback of conventional technique for gray scale images. The proposed algorithm is applied for boat image, microstructure of steel and human head. The contrast enhanced out of the images mentioned is obtained, and the efficiency of the algorithm is evaluated. Simulation results shows that the proposed method can enhance the different types of images effectively. Besides, the proposed contrast enhancement method using modified octagon histogram equalization has comparable performance with black and white stretching and adaptive histogram equalization. 相似文献
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Madhu S. Nair Rekha Lakshmanan M. Wilscy Rao Tatavarti 《Signal, Image and Video Processing》2011,5(1):69-80
In this paper, we evaluate the conventional contrast enhancement techniques [histogram equalization (HE), adaptive HE] and
the recent gray-level grouping method and the fuzzy logic method in order to find out which of these is well suited for automatic
contrast enhancement for satellite images of the ocean, obtained from a variety of sensors. All the techniques evaluated were
based on the principle of transforming the skewed histogram of the original image into a uniform histogram. The performance
of the different contrast enhancement algorithms are evaluated based on the visual quality and the Tenengrad criterion. The
inter comparison of different techniques was carried out on a standard low-contrast image and also three different satellite
images with different characteristics. Based on our study, we advocate that a modified fuzzy logic method elucidated in this
paper is well suited for contrast enhancement of low-contrast satellite images of the ocean. 相似文献
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提出了基于二维直方图分析的二元子图微光图像增强处理算法,根据原始图像的二维直方图分布特征,依据相邻像素的相关性数据,将图像分割成二元子图像,对每个子图像分别进行直方图均衡增强处理,最后合成得到完整的处理图像,通过用信息容量等图像评价参数对实验结果进行分析,表明此算法克服了对整幅图像进行直方图均衡时难以把握局部细节的缺点,得到了具有较好视觉质量的处理后微光图像。 相似文献
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一种基于Otsu法和平台直方图均衡的红外图像增强算法 总被引:1,自引:0,他引:1
针对红外吊舱图像的特点,提出了一种基于Otsu法和平台直方图均衡的红外图像增强算法。首先分析图像的直方图,通过改进的Otsu法把图像分割为天空背景区和地面目标区,背景区以背景峰值与分割后背景区残留目标的局部峰值为依据,采用了一种自适应的方法来产生平台阈值,然后在背景区和目标区的灰度范围内进行直方图均衡化处理。该算法有效地抑制了背景区的过度增强,扩大了目标区的灰度范围,增强了细节部分。实验仿真结果验证了算法的有效性。 相似文献
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A new contrast enhancement algorithm is proposed, which is based on the fact that, for conventional histogram equalization, a uniform input histogram produces an equalized output histogram. Hence before applying histogram equalization, we modify the input histogram in such a way that it is close to a uniform histogram as well as the original one. Thus, the proposed method can improve the contrast while preserving original image features. The main steps of the new algorithm are adaptive gamma transform, exposure-based histogram splitting, and histogram addition. The object of gamma transform is to restrain histogram spikes to avoid over-enhancement and noise artifacts effect. Histogram splitting is for preserving mean brightness, and histogram addition is used to control histogram pits. Extensive experiments are conducted on 300 test images. The results are evaluated subjectively as well as by DE, PSNR EBCM, GMSD, and MCSD metrics, on which, except for the PSNR, the proposed algorithm has some improvements of 2.89, 9.83, 28.32, and 26.38% over the second best ESIHE algorithm, respectively. That is to say, the overall image quality is better. 相似文献