raspberry_pi_camera

Overview

The Raspberry Pi Camera Module v2 replaced the original Camera Module in April 2016. The v2 Camera Module has a Sony IMX219 8-megapixel sensor (compared to the 5-megapixel OmniVision OV5647 sensor of the original camera). The Camera Module can be used to take high-definition video, as well as stills photographs. It’s easy to use for beginners, but has plenty to offer advanced users if you’re looking to expand your knowledge. There are lots of examples online of people using it for time-lapse, slow-motion, and other video cleverness. You can also use the libraries we bundle with the camera to create effects.

Introduction Video

The TurtleBot3 uses Raspberry Pi Camera Module v2 as a default vision sensor. Check this video out that shows how Raspberry Pi Camera Module v2 can be used in TurtleBot3.

Specifications

Hardware Specifications

Items	Specifications
Net price	$25
Size	Around 25 × 24 × 9 mm
Weight	3g
Still resolution	8 Megapixels
Video modes	1080p30, 720p60 and 640 × 480p60/90
Linux integration	V4L2 driver available
C programming API	OpenMAX IL and others available
Sensor	Sony IMX219
Sensor	3280 × 2464 pixels
Sensor	3.68 x 2.76 mm (4.6 mm diagonal)
Pixel size	1.12 µm x 1.12 µm
Optical size	1/4"
Full-frame SLR lens equivalent	35 mm
S/N ratio	36 dB
Dynamic range	67 dB @ 8x gain
Sensitivity	680 mV/lux-sec
Dark current	16 mV/sec @ 60 C
Well capacity	4.3 Ke-
Fixed focus	1 m to infinity
Focal length	3.04 mm
Horizontal field of view	62.2 degrees
Vertical field of view	48.8 degrees
Focal ratio (F-Stop)	2.0

Hardware features

Available	Implemented
Chief ray angle correction	Yes
Global and rolling shutter	Rolling shutter
Automatic exposure control (AEC)	No - done by ISP instead
Automatic white balance (AWB)	No - done by ISP instead
Automatic black level calibration (ABLC)	No - done by ISP instead
Automatic 50/60 Hz luminance detection	No - done by ISP instead
Frame rate up to 120 fps	Max 90fps. Limitations on frame size for the higher frame rates (VGA only for above 47fps)
AEC/AGC 16-zone size/position/weight control	No - done by ISP instead
Mirror and flip	Yes
Cropping	No - done by ISP instead (except 1080p mode)
Lens correction	No - done by ISP instead
Defective pixel cancelling	No - done by ISP instead
10-bit RAW RGB data	Yes - format conversions available via GPU
Support for LED and flash strobe mode	LED flash
Support for internal and external frame synchronisation for frame exposure mode	No
Support for 2 × 2 binning for better SNR in low light conditions	Anything output res below 1296 x 976 will use the 2 x 2 binned mode
Support for horizontal and vertical sub-sampling	Yes, via binning and skipping
On-chip phase lock loop (PLL)	Yes
Standard serial SCCB interface	Yes
Digital video port (DVP) parallel output interface	No
MIPI interface (two lanes)	Yes
32 bytes of embedded one-time programmable (OTP) memory	No
Embedded 1.5V regulator for core power	Yes

Software features

Software features
Picture formats	JPEG (accelerated), JPEG + RAW, GIF, BMP, PNG, YUV420, RGB888
Video formats	raw h.264 (accelerated)
Effects	negative, solarise, posterize, whiteboard, blackboard, sketch, denoise, emboss, oilpaint, hatch, gpen, pastel, watercolour, film, blur, saturation
Exposure modes	auto, night, nightpreview, backlight, spotlight, sports, snow, beach, verylong, fixedfps, antishake, fireworks
Metering modes	average, spot, backlit, matrix
Automatic white balance modes	off, auto, sun, cloud, shade, tungsten, fluorescent, incandescent, flash, horizon
Triggers	Keypress, UNIX signal, timeout
Extra modes	demo, burst/timelapse, circular buffer, video with motion vectors, segmented video, live preview on 3D models

Mechanical Drawing

• Camera Module v2 PDF

Here is the detail specification document: Raspberry Pi Camera Module v2 Datasheet

Camera calibration

1. Prepare the Checkerboard pattern
   Use a black and white Checkerboard, usually 7×6 or 8×6 in size, print it out and attach it to a solid surface, and measure the squares of your checkerboard accurately.

2. Install the ROS 2 Camera Calibration Package
   [Remote PC]

$ sudo apt update
$ sudo apt install ros-${ROS_DISTRO}-camera-calibration
$ source /opt/ros/${ROS_DISTRO}/setup.bash

3. Run the Camera node
   Run the camera node based on the camera package you installed.

• For camera-ros
  [TurtleBot3 SBC]

$ ros2 run camera_ros camera_node --ros-args -p format:='RGB888'

• For v4l2-camera
  Adding -r __ns:=/camera organizes all topics published by the node under the /camera namespace.
  [TurtleBot3 SBC]

$ ros2 run v4l2_camera v4l2_camera_node --ros-args -r __ns:=/camera

4. Run calibration node
   Specify the size of the checkerboard and the size of the squares as execution arguments. The size of the checkerboard is the number of intersections.
   [Remote PC]

$ ros2 run camera_calibration cameracalibrator \
  --size 8x6 --square 0.023 \
  image:=/camera/image_raw camera:=/camera

5. Proceed with the calibration
   When a checkerboard is detected, each intersection is connected. Modify the position of the checkerboard until the green bar on the right is filled to activate the button.
   !calibration

6. Apply calibration
   Use the results to modify the format of the calibration yaml file you created when you installed the camera package.
   [Result]

   **** Calibrating ****
   mono pinhole calibration...
   D = [0.03044862133677453, 1.051149543007478, -0.010043417242237722, -0.004408001911603297, 0.0]
   K = [630.410302346659, 0.0, 153.7660597801437, 0.0, 630.2122426630051, 112.97681709327331, 0.0, 0.0, 1.0]
   R = [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
   P = [638.0872192382812, 0.0, 152.86851810362077, 0.0, 0.0, 636.0022583007812, 111.61012624808154, 0.0, 0.0, 0.0, 1.0, 0.0]
   None
   # oST version 5.0 parameters
   
   
   [image]
   
   width
   320
   
   height
   240
   
   [narrow_stereo]
   
   camera matrix
   630.410302 0.000000 153.766060
   0.000000 630.212243 112.976817
   0.000000 0.000000 1.000000
   
   distortion
   0.030449 1.051150 -0.010043 -0.004408 0.000000
   
   rectification
   1.000000 0.000000 0.000000
   0.000000 1.000000 0.000000
   0.000000 0.000000 1.000000
   
   projection
   638.087219 0.000000 152.868518 0.000000
   0.000000 636.002258 111.610126 0.000000
   0.000000 0.000000 1.000000 0.000000

Trouble Shooting

The error message Unable to open camera calibration file [/home/ubuntu/.ros/camera_info/<camera_name>.yaml] appears when the camera calibration file is missing.

1. Create the calibration directory (if it doesn't exist)
   [TurtleBot3 SBC]

$ mkdir -p /home/ubuntu/.ros/camera_info/

2. Create the calibration file
   [TurtleBot3 SBC]

$ sudo nano /home/ubuntu/.ros/camera_info/<camera_name>.yaml

Calibration yaml file example
Make sure to update the image_width, image_height values and camera_name to match your actual camera settings. Ensure the camera_name in the .yaml file matches the actual camera name.

image_width: 320   # Update to your camera's actual resolution
image_height: 240   # Update to your camera's actual resolution
camera_name: imx219__base_soc_i2c0mux_i2c_1_imx219_10_320x240   # Replace with the actual camera name
frame_id: camera
camera_matrix:
  rows: 3
  cols: 3
  data: [161.0352, 0, 99.6340, 0, 160.4337, 77.6267, 0, 0, 1]
distortion_model: plumb_bob
distortion_coefficients:
  rows: 1
  cols: 5
  data: [0.1639958, -0.2718400, 0.0010558, -0.0016656, 0]
rectification_matrix:
  rows: 3
  cols: 3
  data: [1, 0, 0, 0, 1, 0, 0, 0, 1]
projection_matrix:
  rows: 3
  cols: 4
  data: [164.6242, 0, 99.2051, 0, 0, 164.5522, 77.7529, 0, 0, 0, 1, 0]

References

• Raspberry Pi Camera Module Specifications
• Hardware Configuration
• Software Configuration
• Getting Started
• Purchase