Mahotas 简明教程

Mahotas - Loading Image as Grey

灰度图像是一种黑白图像或灰色单色图像，仅由灰色阴影组成。对比度范围从黑色到白色，分别是最低强度到最高强度。

The grayscale images are a kind of black−and−white images or gray monochrome, consisting of only shades of gray. The contrast ranges from black to white, which is the weakest intensity to the strongest respectively.

灰度图像仅包含亮度信息，但不包含颜色信息。这是白色表示最高亮度（亮度），而黑色表示零亮度的主要原因，介于两者之间的所有内容都由灰色阴影组成。

The grayscale image only contains the brightness information and no color information. This is the reason of white being the maximum luminance (brightness) and black being the zero luminance, and everything in between consists shades of gray.

Loading Grayscale Images

在 Mahotas 中，加载灰度图像涉及读取一个图像文件，该文件仅包含每个像素的强度值。生成图像表示为一个 2D 数组，其中每个元素表示像素的强度。

In Mahotas, loading grayscale images involves reading an image file that only contains intensity values for each pixel. The resulting image is represented as a 2D array, where each element represents the intensity of a pixel.

以下是 Mahotas 中加载灰度图像的基本语法 −

Following is the basic syntax for loading grayscale Images in Mahotas −

mahotas.imread('image.file_format', as_grey=True)

其中， 'image.file_format' 是要加载的图像的实际路径和格式， 'as_grey=True' 作为参数传递，表示我们要将图像加载为灰度。

Where, 'image.file_format' is the actual path and format of the image you want to load and 'as_grey=True' is passed as an argument to indicate that we want to load the image as grayscale.

Example

以下是 Mahotas 中加载灰度图像的示例 −

Following is an example of loading a grayscale image in Mahotas −

import mahotas as ms
import matplotlib.pyplot as mtplt
# Loading grayscale image
grayscale_image = ms.imread('nature.jpeg', as_grey=True)
# Displaying grayscale image
mtplt.imshow(grayscale_image, cmap='gray')
mtplt.axis('off')
mtplt.show()

执行以上代码后，我们得到如下所示的输出 −

After executing the above code, we get the output as shown below −

loading grayscale images

Loading Different Image Formats as Grayscale

图像格式是指用于以数字方式存储和编码图像的不同文件格式。每种格式都有自己的规范、特性和压缩方法。

The image format refers to the different file formats used to store and encode images digitally. Each format has its own specifications, characteristics, and compression methods.

Mahotas 提供了多种图像格式，包括 JPEG、PNG、BMP、TIFF 和 GIF 等常见格式。我们可以将任何这些格式中灰度图像的文件路径传递给 imread() 函数。

Mahotas provides a wide range of image formats, including common formats like JPEG, PNG, BMP, TIFF, and GIF. We can pass the file path of a grayscale image in any of these formats to the imread() function.

Example

在此示例中，我们通过使用 imread() 函数加载不同格式的灰度图像来说明 Mahotas 的多功能性。每张加载的图像都存储在单独的变量中 −

In this example, we demonstrate the versatility of Mahotas by loading grayscale images in different formats using the imread() function. Each loaded image is stored in a separate variable −

import mahotas as ms
import matplotlib.pyplot as mtplt
# Loading JPEG image
image_jpeg = ms.imread('nature.jpeg', as_grey = True)
# Loading PNG image
image_png = ms.imread('sun.png',as_grey = True)
# Loading BMP image
image_bmp = ms.imread('sea.bmp',as_grey = True)
# Loading TIFF image
image_tiff = ms.imread('tree.tiff',as_grey = True)
# Creating a figure and subplots
fig, axes = mtplt.subplots(2, 2)
# Displaying JPEG image
axes[0, 0].imshow(image_jpeg)
axes[0, 0].axis('off')
axes[0, 0].set_title('JPEG Image')
# Displaying PNG image
axes[0, 1].imshow(image_png)
axes[0, 1].axis('off')
axes[0, 1].set_title('PNG Image')
# Displaying BMP image
axes[1, 0].imshow(image_bmp)
axes[1, 0].axis('off')
axes[1, 0].set_title('BMP Image')
# Displaying TIFF image
axes[1, 1].imshow(image_tiff)
axes[1, 1].axis('off')
axes[1, 1].set_title('TIFF Image')
# Adjusting the spacing and layout
mtplt.tight_layout()
# Showing the figure
mtplt.show()

显示的图像如下 −

The image displayed is as follows −

different grayscale formats

Using the Color Mode 'L'

“L”颜色模式表示亮度，它是颜色亮度的度量。它源自 RGB（红色、绿色、蓝色）颜色模型，其中红色、绿色和蓝色通道的强度值组合在一起以计算灰度强度。“L”模式舍弃颜色信息并仅使用灰度强度值表示图像。

The "L" color mode represents luminance, which is a measure of the brightness of a color. It is derived from the RGB (Red, Green, Blue) color model, in which the intensity values of the red, green and blue channels are combined to calculate the grayscale intensity. The "L" mode discards the color information and represents the image using only the grayscale intensity values.

要通过在 mahotas 中将颜色模式指定为“L”加载图像作为灰色，我们需要将参数 as_grey='L' 传递给 imread() 函数。

To load image as grey by specifying the color mode as "L" in mahotas, we need to pass the parameter as_grey='L' to the imread() function.

Example

在这里，我们正在加载灰度图像并将颜色模式指定为“L” −

In here, we are loading a grayscale image and specifying the color mode as 'L' −

import mahotas as ms
import matplotlib.pyplot as mtplt
# Loading grayscale image
image = ms.imread('sun.png')
grayscale_image = ms.imread('sun.png', as_grey = 'L')
# Creating a figure and subplots
fig, axes = mtplt.subplots(1, 2)
# Displaying original image
axes[0].imshow(image)
axes[0].axis('off')
axes[0].set_title('Original Image')
# Displaying grayscale image
axes[1].imshow(grayscale_image, cmap='gray')
axes[1].axis('off')
axes[1].set_title('Grayscaled Image')
# Adjusting the spacing and layout
mtplt.tight_layout()
# Showing the figure
mtplt.show()

以下是上面代码的输出： -

Following is the output of the above code −

color mode l