[树莓派] : 如何用树莓派利用摄像头进行简单的人脸识别【how to use IR camera +raspberrypi 3b+ in python】

梦里梦外; 2021-11-18 01:28 185阅读 0赞

> \# how to use IR camera +raspberrypi 3b+ in python:
> 
> 1.connect the camera module: shut down the respberrypi power,connect the camera
> 
> 2.open the ir camera： use python IDE

**目录**

Introduction

What you will need

Raspberry Pi computer with a Camera Module port

Raspberry Pi Camera Module

Connect the Camera Module

How to control the Camera Module via the command line

How to control the Camera Module with Python code

Recording video with Python code

How to change the image settings and add image effects

Set the image resolution

Add text to your image

Change the look of the added text

Change the brightness of the preview

Change the contrast of the preview

--------------------

## Introduction ##

Learn how to connect the Raspberry Pi Camera Module to your Raspberry Pi and take pictures, record video, and apply image effects.

## What you will need ##

### Raspberry Pi computer with a Camera Module port ###

All current models of Raspberry Pi have a port for connecting the Camera Module.

![Raspberry Pi 3B+ with Camera Module port labelled][Raspberry Pi 3B_ with Camera Module port labelled]

**Note:** If you want to use a Raspberry Pi Zero, you need a Camera Module ribbon cable that fits the Raspberry Pi Zero’s smaller Camera Module port.

### Raspberry Pi Camera Module ###

![Raspberry Pi Camera Module][]

## Connect the Camera Module ##

**Ensure your Raspberry Pi is turned off.**

1.  Locate the Camera Module port
2.  Gently pull up on the edges of the port’s plastic clip
3.  Insert the Camera Module ribbon cable; make sure the cable is the right way round
4.  Push the plastic clip back into place

*  Start up your Raspberry Pi.
 *  Go to the main menu and open the **Raspberry Pi Configuration** tool.
    
    ![Raspberry Pi Configuration Tool][]
 *  Select the **Interfaces** tab and ensure that the camera is **enabled**:
    
    ![Camera enabled][]
 *  Reboot your Raspberry Pi.

## How to control the Camera Module via the command line ##

Now your Camera Module is connected and the software is enabled, try out the command line tools `raspistill` and `raspivid`.

*  Open a terminal window by clicking the black monitor icon in the taskbar:

*  Type in the following command to take a still picture and save it to the Desktop:

raspistill -o Desktop/image.jpg

![raspistill command entered into the terminal][]

*  Press Enter to run the command.

When the command runs, you can see the camera preview open for five seconds before a still picture is taken.

*  Look for the picture file icon on the Desktop, and double-click the file icon to open the picture.
    
    ![Image on Desktop][]

By adding different options, you can set the size and look of the image the `raspistill` command takes.

*  For example, add `-h` and `-w` to change the height and width of the image:

raspistill -o Desktop/image-small.jpg -w 640 -h 480

*  Now record a video with the Camera Module by using the following `raspivid` command:

raspivid -o Desktop/video.h264

*  In order to play the video file, double-click the `video.h264` file icon on the Desktop to open it in VLC Media Player.

## How to control the Camera Module with Python code ##

The Python `picamera` library allows you to control your Camera Module and create amazing projects.

You should see the camera preview open for five seconds, and then a still picture should be captured. As the picture is being taken, you can see the preview briefly adjust to a different resolution.

Your new image should be saved to the Desktop.

The camera should take one picture every five seconds. Once the fifth picture is taken, the preview closes.

Your Raspberry Pi should open a preview, record 5 seconds of video, and then close the preview.

*  Open a Python 3 editor, such as **Thonny Python IDE**:
 *  Open a new file and save it as `camera.py`.
    
    **Note:** it’s important that you **never save the file as `picamera.py`**.
 *  Enter the following code:
    
        from picamera import PiCamera
        from time import sleep
        
        camera = PiCamera()
        
        camera.start_preview()
        sleep(5)
        camera.stop_preview()
 *  Save and run your program. The camera preview should be shown for five seconds and then close again.
 *  If your preview is upside-down, you can rotate it by 180 degrees with the following code:
    
        camera = PiCamera()
        camera.rotation = 180
    
    You can rotate the image by `90`, `180`, or `270` degrees. To reset the image, set `rotation` to `0` degrees.
 *  Make the camera preview see-through by setting an `alpha` level:
    
        camera.start_preview(alpha=200)
    
    The `alpha` value can be any number between `0` and `255`.
 *  It’s best to make the preview slightly see-through so you can see whether errors occur in your program while the preview is on.
 *  Now use the Camera Module and Python to take some still pictures.
 *  Amend your code to add a `camera.capture()` line:
    
        camera.start_preview()
        sleep(5)
        camera.capture('/home/pi/Desktop/image.jpg')
        camera.stop_preview()
    
    **Note:** it’s important to `sleep` for at least two seconds before capturing an image, because this gives the camera’s sensor time to sense the light levels.
 *  Run the code.
 *  Now add a loop to take five pictures in a row:
    
        camera.start_preview()
        for i in range(5):
            sleep(5)
            camera.capture('/home/pi/Desktop/image%s.jpg' % i)
        camera.stop_preview()
    
    The variable `i` counts how many times the loop has run, from `0` to `4`. Therefore, the images get saved as `image0.jpg`, `image1.jpg`, and so on.
 *  Look at your Desktop to find the five new pictures.
    
     *  Run the code again and hold the Camera Module in position.
     *  ## Recording video with Python code ##
        
        Now record a video!
     *  Amend your code to remove `capture()` and instead add `start_recording()` and `stop_recording()`
        
        Your code should look like this now:
        
            camera.start_preview()
            camera.start_recording('/home/pi/Desktop/video.h264')
            sleep(5)
            camera.stop_recording()
            camera.stop_preview()
     *  Run the code.

## How to change the image settings and add image effects ##

The Python `picamera` software provides a number of effects and configurations to change how your images look.

**Note:** some settings only affect the preview and not the captured image, some affect only the captured image, and many others affect both.

### Set the image resolution ###

You can change the `resolution` of the image that the Camera Module takes.

By default, the image resolution is set to the resolution of your monitor. The maximum resolution is 2592×1944 for still photos, and 1920×1080 for video recording.

Use the following code to set the `resolution` to maximum and take a picture.

**Note:** you also need to set the frame rate to `15` to enable this maximum resolution.

camera.resolution = (2592, 1944)
    camera.framerate = 15
    camera.start_preview()
    sleep(5)
    camera.capture('/home/pi/Desktop/max.jpg')
    camera.stop_preview()

The minimum resolution is 64×64.

### Add text to your image ###

You can add text to your image using the command `annotate_text`.

### Change the look of the added text ###

It’s also possible to change the text colour.

### Change the brightness of the preview ###

You can change how bright the preview appears. The default brightness is `50`, and you can set it to any value between `0` and `100`.

### Change the contrast of the preview ###

Similarly to the preview brightness, you can change the contrast of the preview.

The default effect is `none`.

本篇文章转载自：[https://projects.raspberrypi.org/en/projects/getting-started-with-picamera][https_projects.raspberrypi.org_en_projects_getting-started-with-picamera]

更多请关注“树莓派官网”：[https://projects.raspberrypi.org/en][https_projects.raspberrypi.org_en]

*  Try taking a picture with the minimum resolution.
 *  Run this code to try it:
    
        camera.start_preview()
        camera.annotate_text = "Hello world!"
        sleep(5)
        camera.capture('/home/pi/Desktop/text.jpg')
        camera.stop_preview()
 *  Set the text size with the following code:
    
        camera.annotate_text_size = 50
    
    You can set the text size to anything between `6` to `160`. The default size is `32`.
 *  First of all, add `Color` to your `import` line at the top of the program:
    
        from picamera import PiCamera, Color
 *  Then below the `import` line, amend the rest of your code so it looks like this:
    
        camera.start_preview()
        camera.annotate_background = Color('blue')
        camera.annotate_foreground = Color('yellow')
        camera.annotate_text = " Hello world "
        sleep(5)
        camera.stop_preview()
 *  Run the following code to try this out:
    
        camera.start_preview()
        camera.brightness = 70
        sleep(5)
        camera.capture('/home/pi/Desktop/bright.jpg')
        camera.stop_preview()
 *  The following loop adjusts the brightness and also adds text to display the current brightness level:
    
        camera.start_preview()
        for i in range(100):
            camera.annotate_text = "Brightness: %s" % i
            camera.brightness = i
            sleep(0.1)
        camera.stop_preview()
 *  Run the following code to try this out:
    
        camera.start_preview()
        for i in range(100):
            camera.annotate_text = "Contrast: %s" % i
            camera.contrast = i
            sleep(0.1)
        camera.stop_preview()
 *  Pick an image effect and try it out:
 *      camera.start_preview()
        camera.image_effect = 'colorswap'
        sleep(5)
        camera.capture('/home/pi/Desktop/colorswap.jpg')
        camera.stop_preview()
 *  Run this code to loop over **all** the image effects with `camera.IMAGE_EFFECTS`:
    
        camera.start_preview()
        for effect in camera.IMAGE_EFFECTS:
            camera.image_effect = effect
            camera.annotate_text = "Effect: %s" % effect
            sleep(5)
        camera.stop_preview()
    
    ![Effects][]

![Raspberry Pi with Camera Module attached][]

[Raspberry Pi 3B_ with Camera Module port labelled]: /images/20211116/fc0adcdb8e31483f8ea9e2e03a03f2c7.png
[Raspberry Pi Camera Module]: /images/20211116/05f276fa41dc47cea0c2fae732f2b95c.png
[Raspberry Pi Configuration Tool]: /images/20211116/c5af5ab6e7a24ccaad85614f9e445c4c.png
[Camera enabled]: /images/20211116/faa1d60239614e60b72735a516ae370b.png
[raspistill command entered into the terminal]: /images/20211116/6ce4ae8b32d7439095a30c7a82b36f5e.png
[Image on Desktop]: /images/20211116/5f6033fb210a40218149eb458fcc1a70.png
[https_projects.raspberrypi.org_en_projects_getting-started-with-picamera]: https://projects.raspberrypi.org/en/projects/getting-started-with-picamera
[https_projects.raspberrypi.org_en]: https://projects.raspberrypi.org/en
[Effects]: /images/20211116/1dd6e4fd90874612a22e2fcad969ae3c.png
[Raspberry Pi with Camera Module attached]: /images/20211116/c79153c1b78c4468aed6bac4abc87f7c.png