如果构成图像的像素数量少、像素的尺寸大，可观察到的原始图像细节较少，图像的空间分辨率低；反之，像素数量多，图像的空间分辨率高。描述一幅图像需要的像素数量是由每个像素的大小和整个图像的尺寸决定的。在空间分辨率一定的条件下，图像大比图像小需要的像素多，每个单独像素的大小决定图像空间分辨率。若图像矩阵大小固定，视野增加时，图像空间分辨率降低。灰度级数影响着数字图像的密度分辨率。计算机处理和存储数字图像采用的是二进制数，ADC将连续变化的灰度值转化为一系列离散的整数灰度值，量化后的整数灰度值又称为灰度级(gray level)或灰阶(gray scale)。量化后灰度级的数量由2N决定，N是二进制数的位数，称为位(bit)，用来表示每个像素的灰度精度。
显示器上呈现的黑白图像的各点表现的不同深度灰度称为
A．噪声
B．量化
C．比特
D．灰阶
E．像素
参考答案：D
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| These days, it is easier for us to travel to other countries than ever before. However, there is a big difficulty that most of us _1_ when we meet people in other countries--we cannot communicate with them. There are _2_ where English is still not spoken, though it is the most widely known language. So, wouldn't it be _3_ if there was one language that could be understood by anyone anywhere in the world? Esperanto that was created in 1887 may be the world's _4_ truly international language. In fact, although _5_ artificial (人造的) languages have been already created, only Esperanto has had much success. Its learner say that it is about four times _6_ to learn than other languages. Spelling and pronunciation are both easy, too. For example, it does not have silent _7_ like the "h" in "hour". If you _8_ a word, you can spell it without any difficulty. The grammar is also as simple as possible: only sixteen basic _9_, no irregular verbs (不规则动词), only six verb endings. In short, Esperanto should be attractive as a language to learn, _10_ there is a problem: how many people have met anyone who can really speak it? Anyway, we hope that some day one language can be mastered easily by anyone. | ||||
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