What do we know about how humans choose grey levels for images?
What do we know about how humans choose grey levels for images?
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我们对人类如何选择图像灰度级了解多少？
DOI：
10.1167/10.7.406
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发表时间：
2010
影响因子：
1.8
通讯作者：
Bloj M
中科院分区：
文献类型：
--
作者：
Bloj M
从32000多年前的洞穴壁画到现在使用木炭或粉笔的艺术家的作品，人类使用不同级别的单一颜色(如灰色)来描绘我们周围丰富多彩的世界。这项研究的目的是调查我们是如何构建这些单色图像的；我们是否像其他人一样选择了相同的灰度级相对顺序？图像内容和对比度如何影响我们的灰色设置？为此，我们在校准的CRT上呈现了5个简化的卡通类型的彩色图像。这些图像以4个不同的版本显示：其中两个版本的图像内容是可识别的(一个在每个对象周围添加了黑色轮廓，另一个没有)。在另外两个版本中，图像中的每个像素与其他相同颜色的像素被分组为矩形区域，其方式使图像的内容变得抽象，同时保留由特定颜色占据的区域。其中一个版本的每个颜色区域周围都有一个黑色的轮廓；另一个版本没有。六位天真的普通彩色观察者使用数码“重新着色工具”创建了随机呈现的彩色图像的灰度版本。对参与者对不同版本图像的设置进行的初步分析表明，添加黑色轮廓似乎不会影响所选的灰度级。更令人惊讶的是，从可识别场景到抽象矩形的内容变化似乎也没有改变灰度级。尽管每个人的绝对设置不同，但对于给定的图像，总体排名在很大程度上保持在参与者之间。对于我们选择的一组测试图像，驱动灰色设置的最具影响力的因素是彩色补丁的感知亮度，而不是图像内容或对比度。
From cave paintings that are more than 32000 years old to the work of current artists using charcoal or pastels humans have used different levels of a single colour (eg greyscales) to portray the colourful world that surrounds us. The aim of this study was to investigate how we construct these monochromatic images; do we choose the same relative order of grey levels as other people? How does image content and contrast influence our grey settings? For this purpose, we presented, on a calibrated CRT, 5 simplified cartoon-type colourful images. These images where shown in 4 different versions: two where the content of image was recognisable (one with added black outline around each object, the other without). In the other two versions each pixel in an image was grouped with other pixels of the same colour into rectangular areas in a way that made the content of image abstract while preserving the area taken up by a particular colour. One of these versions had a black outline around each colour area; the other did not. Six naïve, colour normal observers used a digital ‘re-colouring tool’to create greyscales version of the randomly presented colour images. Preliminary analyses of participants' settings for different version of the images indicate that the addition of black outlines does not seem to affect chosen grey levels. More surprisingly, the change in content from a recognisable scene to abstract rectangles also seems to leave grey levels un-changed. Although each individual's absolute settings were different, the overall ranking was largely preserved across participants for a given image. For our chosen set of test images, the most influential factor driving grey settings was the perceived lightness of the coloured patch, not image content or contrast.