IMX219 – Auto Focus Camera

The autofocus camera is an advanced IMX219 camera module for Jetson Nano/Xavier NX board. It helps to focus the object in close range from 5cm~30cm, within this range the standard fixed focus camera can not get sharp focus and the image looks burry. All the focus procedure is controlled by the software without manually adjust the lens barrel.

Order Information

How to use ArduCam IMX219 AF Module on Jetson Nano

1. Download Arducam’s Jetson Nano repository.

git clone https://github.com/ArduCAM/Nvidia_Jetson.git

2. Enter the folder with the autofocus demo

cd Nvidia_Jetson/IMX219_AutoFocus

3. Run the demo​​​​​

This example python code is modified from JetsonHacks sample code in order to work with Arducam Autofocus IMX219 camera module.

sudo python Autofocus.py

# MIT License
# Copyright (c) 2019 JetsonHacks
# See license
# Using a CSI camera (such as the Raspberry Pi Version 2) connected to a 
# NVIDIA Jetson Nano Developer Kit using OpenCV
# Drivers for the camera and OpenCV are included in the base image

import cv2
import numpy as py
import os

def focusing(val):
	value = (val << 4) & 0x3ff0
	data1 = (value >> 8) & 0x3f
	data2 = value & 0xf0
	os.system("i2cset -y 6 0x0c %d %d" % (data1,data2))
	
def sobel(img):
	img_gray = cv2.cvtColor(img,cv2.COLOR_RGB2GRAY)
	img_sobel = cv2.Sobel(img_gray,cv2.CV_16U,1,1)
	return cv2.mean(img_sobel)[0]

def laplacian(img):
	img_gray = cv2.cvtColor(img,cv2.COLOR_RGB2GRAY)
	img_sobel = cv2.Laplacian(img_gray,cv2.CV_16U)
	return cv2.mean(img_sobel)[0]


# gstreamer_pipeline returns a GStreamer pipeline for capturing from the CSI camera
# Defaults to 1280x720 @ 60fps 
# Flip the image by setting the flip_method (most common values: 0 and 2)
# display_width and display_height determine the size of the window on the screen

def gstreamer_pipeline (capture_width=1280, capture_height=720, display_width=1280, display_height=720, framerate=60, flip_method=0) :   
    return ('nvarguscamerasrc ! ' 
    'video/x-raw(memory:NVMM), '
    'width=(int)%d, height=(int)%d, '
    'format=(string)NV12, framerate=(fraction)%d/1 ! '
    'nvvidconv flip-method=%d ! '
    'video/x-raw, width=(int)%d, height=(int)%d, format=(string)BGRx ! '
    'videoconvert ! '
    'video/x-raw, format=(string)BGR ! appsink'  % (capture_width,capture_height,framerate,flip_method,display_width,display_height))

def show_camera():
    max_index = 10
    max_value = 0.0
    last_value = 0.0
    dec_count = 0
    focal_distance = 10
    focus_finished = False
    # To flip the image, modify the flip_method parameter (0 and 2 are the most common)
    print gstreamer_pipeline(flip_method=0)
    cap = cv2.VideoCapture(gstreamer_pipeline(flip_method=0), cv2.CAP_GSTREAMER)
    if cap.isOpened():
        window_handle = cv2.namedWindow('CSI Camera', cv2.WINDOW_AUTOSIZE)
        # Window 
        while cv2.getWindowProperty('CSI Camera',0) >= 0:
            ret_val, img = cap.read()
            cv2.imshow('CSI Camera',img)
            
            if dec_count < 6 and focal_distance < 1000:
                #Adjust focus
                focusing(focal_distance)
                #Take image and calculate image clarity
                val = laplacian(img)
                #Find the maximum image clarity
                if val > max_value:
                    max_index = focal_distance
                    max_value = val
                    
                #If the image clarity starts to decrease
                if val < last_value:
                    dec_count += 1
                else:
                    dec_count = 0
                #Image clarity is reduced by six consecutive frames
                if dec_count < 6:
                    last_value = val
                    #Increase the focal distance
                    focal_distance += 10

            elif not focus_finished:
                #Adjust focus to the best
                focusing(max_index)
                focus_finished = True
            # This also acts as 
            keyCode = cv2.waitKey(16) & 0xff
            # Stop the program on the ESC key
            if keyCode == 27:
                break
            elif keyCode == 10:
                max_index = 10
                max_value = 0.0
                last_value = 0.0
                dec_count = 0
                focal_distance = 10
                focus_finished = False
        cap.release()
        cv2.destroyAllWindows()
    else:
        print 'Unable to open camera'


if __name__ == '__main__':
    show_camera()