Pillow is a relatively basic image processing library in Python. It is mainly used for basic image processing, such as cropping images, adjusting image sizes and images. Color processing, etc. Compared with Pillow, OpenCV and Scikit-image have richer functions and are therefore more complex to use. They are mainly used in fields such as machine vision and image analysis, such as the well-known "face recognition" application.
2. Features
Supports a wide range of formats
Pillow supports a wide range of image formats, such as "jpeg", "png", "bmp", "gif", "ppm", "tiff" etc. At the same time, it also supports mutual conversion between image formats. In short, Pillow can process images in almost any format
Provides rich functions
Pillow provides rich image processing functions, which can be summarized in two aspects:
Image archiving includes creating thumbnails, generating preview images, image batch processing, etc.; while image processing includes resizing images, cropping images, pixel processing, adding filters, image color processing, etc.
Image archiving
Image processing
Used with GUI tools
3. Installation
pip install pillow
导包
imoprt PIL
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2. Image object
1. Instantiation object
1.1 Instantiation
Guide package
from PIL import Image
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Use the open method
im = PIL.Image.open(fp) # 导入图片
im.show() # 展示图片
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fp: Picture path
Use the open method
im = Image.new(mode,size,color) # 创建图片
im.show() # 展示图片
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The parameter description is as follows:
mode: image mode, string parameters, such as RGB (true color image), L (grayscale image), CMYK (color map printing mode), etc.
size: image size, tuple parameters (width, height) represent the pixel size of the image
color: image color, the default value is 0 for black, parameter value Supports (R,G,B) triplet number format, hexadecimal value of color and English word of color
1.2 Image mode
mode
Description
1
1 bit pixel (value range 0-1), 0 means black ,1 means white,monochrome channel.
L
8-bit pixel (value range 0 -255), grayscale image, monochrome channel.
P
8-bit pixel, using palette mapping to any other mode, monochrome channel.
RGB
3 x 8-bit pixels, true color, three color channels, the value range of each channel is 0-255.
RGBA
4 x 8-bit pixels, true color, transparent channel, four color channels.
CMYK
4 x 8-bit pixels, four color channels, suitable for printing pictures.
YCbCr
3 x 8-bit pixels, color video format, three color channels.
LAB
3 x 8-bit pixels, L * a * b color space, three color channels
HSV
3 x 8-bit pixels, hue, saturation, value color space, three color channels.
变量option的 font 用于指定所用字体。它应该是类ImangFont的一个实例,使用ImageFont模块的load()方法从文件中加载的
变量options的fill给定文本的颜色
2.11 textsize
语法:
draw.textsize(string, options)
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返回给定字符串的大小,以像素为单位
变量option的 font 用于指定所用字体。它应该是类ImangFont的一个实例,使用ImageFont模块的load()方法从文件中加载的
七、 Image与Numpy
from PIL import Image
import numpy as np
im = Image.open("./a.jpg")
print(np.asarray(im)) # 三维数组
na = np.asarray(im) # 将图片转换为数组
na[0][0][0] = 0 # 修改数组的值
im_new = Image.fromarray(na) # 将数组转换为图片
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