Camera Object

The Camera object is used to implement image capture and processing functions for MIPI cameras. It includes several methods such as open_cam, open_vps, get_img, set_img, and close_cam. Detailed descriptions are provided below:

open_cam

【Function Description】

Opens the MIPI camera on the specified channel and configures the camera's output frame rate and resolution format.

【Function Declaration】

Camera.open_cam(pipe_id, video_index, fps, width, height, raw_height, raw_width)

【Parameter Description】

Parameter Name	Description	Value Range
pipe_id	Pipeline channel ID corresponding to the camera	Starts from 0 by default; range: 0–7
video_index	Host ID corresponding to the camera; -1 indicates auto-detection	Values: -1, 0, 1, 2 (see "Host ID Selection" section for details)
fps	Camera output frame rate	Depends on camera model; default: 30
width	Final output image width of the camera	Depends on camera model; default: 1920
height	Final output image height of the camera	Depends on camera model; default: 1080
raw_height	Original RAW image output height of the camera	Depends on camera model; default: 1920
raw_width	Original RAW image output width of the camera	Depends on camera model; default: 1080

【Usage】

#create camera object
camera = libsrcampy.Camera()

#open MIPI Camera, fps: 30, solution: 1080p
ret = camera.open_cam(0, -1, 30, 1920, 1080)

【Return Value】

Return Value	Description
0	Success
-1	Failure

【Notes】

The parameters width and height support input of type list, which enables the camera to output multiple resolutions simultaneously. The list supports up to 6 scaled-down outputs, with scaling ratios in the range [1, 1/64) relative to the camera’s native resolution. Example usage:

ret = cam.open_cam(0, -1, 30, [1920, 1280], [1080, 720])

The parameters raw_height and raw_width should only be set when the camera does not use its default resolution. For example, when using an IMX477 camera and wishing to output both 4K (3840×2160) and 1080P (1920×1080) simultaneously, you can use:

cam.open_cam(0, -1, 10, [3840, 1920], [2160, 1080], 3000, 4000)

Currently supported camera resolutions are listed below:

Camera	Resolution
IMX219	1920x1080@30fps (default)

Note!

Switching the IMX477 camera from 1080P resolution to another resolution requires a manual reset. You can perform this reset on the board by running hobot_reset_camera.py.

Note!

The S100 chip has alignment requirements for VPS output:

Output width must be aligned to 16 bytes.
Output height must be aligned to 2 bytes.

If your configured width or height does not meet these alignment requirements, an error will be reported.

【Reference Code】

None

open_vps

【Function Description】

Enables the VPS (Video Processing System) image processing functionality for the specified camera channel, supporting operations such as scaling and cropping on the input image.

【Function Declaration】

Camera.open_vps(pipe_id, proc_mode, src_width, src_height, dst_width, dst_height, crop_rect, rotate, src_size, dst_size)

【Parameter Description】

Parameter Name	Description	Value Range
pipe_id	Pipeline channel ID corresponding to the camera	Starts from 0 by default; range: 0–7
proc_mode	Image processing mode (supports scaling, cropping + scaling)	Values 1–4: `scaling`, `cropping + scaling`
src_width	Input image width	Depends on camera output width
src_height	Input image height	Depends on camera output height
dst_width	Output image width	[1, 1/64) × input width
dst_height	Output image height	[1, 1/64) × input height
crop_rect	Cropping region dimensions in format [x, y]	Must not exceed input image dimensions
rotate	Rotation angle (currently unsupported; max two channels support rotation)	Values 0–3: `no rotation`, `90°`, `180°`, `270°`
src_size	Reserved parameter	Not required by default
dst_size	Reserved parameter	Not required by default

【Usage】

#create camera object
camera = libsrcampy.Camera()

#enable vps function
ret = camera.open_vps(1, 1, 1920, 1080, 512, 512)

【Return Value】

Return Value	Description
0	Success
-1	Failure

Note!

VPS supports up to 6 output channels and only downscaling. Scaling ratio range: [1, 1/64). Multi-channel configurations are passed via list parameters.
Image cropping uses the top-left corner as the origin and crops according to the specified dimensions.
Cropping is applied before scaling and rotation. Multi-channel configurations are passed via list parameters.

Note!

The S100 chip has alignment requirements for VPS output:

Output width must be aligned to 16 bytes.
Output height must be aligned to 2 bytes.

If your configured width or height does not meet these alignment requirements, an error will be reported.

#creat camera object
camera = libsrcampy.Camera()

#enable vps function
#input: 4k, output0: 1080p, output1: 720p
#ouput0 croped by [2560, 1440]
ret = camera.open_vps(0, 1, 3840, 2160, [1920, 1280], [1080, 720], [2560, 1440])

【Reference Code】
None

get_img

【Function Description】

Retrieves the image output from the camera object. This method must be called after open_cam or open_vps.

【Function Declaration】

Camera.get_img(module, width, height)

【Parameter Description】

Parameter Name	Description	Value Range
module	Module from which to retrieve the image	Default: 2
width	Width of the image to retrieve	Must match the output width configured in `open_cam` or `open_vps`
height	Height of the image to retrieve	Must match the output height configured in `open_cam` or `open_vps`

【Usage】

cam = libsrcampy.Camera()

#open MIPI Camera, fps: 30, solution: 1080p
ret = cam.open_cam(0, 1, 30, 1920, 1080)

#wait for 1s
time.sleep(1)

#get one image from camera
img = cam.get_img(2)

【Return Value】

Return Value	Description
0	Success
-1	Failure

【Notes】 This method must be called after open_cam or open_vps.

【Reference Code】

import sys, os, time

from hobot_vio import libsrcampy

def test_camera():
    cam = libsrcampy.Camera()

    # open MIPI camera, fps: 30, resolution: 1080p
    ret = cam.open_cam(0, 1, 30, 1920, 1080)
    print("Camera open_cam return:%d" % ret)

    # wait for 1s
    time.sleep(1)

    # get one image from camera   
    img = cam.get_img(2)
    if img is not None:
        # save file
        fo = open("output.img", "wb")
        fo.write(img)
        fo.close()
        print("camera save img file success")
    else:
        print("camera save img file failed")
    
    # close MIPI camera
    cam.close_cam()
    print("test_camera done!!!")

test_camera()

set_img

【Function Description】

Input image data into the vps module and trigger image processing.

【Function Declaration】

Camera.set_img(img)

【Parameter Description】

Parameter Name	Description	Value Range
img	Image data to be processed	Must match the VPS input resolution

【Usage】

camera = libsrcampy.Camera()

# enable vps function, input: 1080p, output: 512x512
ret = camera.open_vps(1, 1, 1920, 1080, 512, 512)
print("Camera vps return:%d" % ret)

fin = open("output.img", "rb")
img = fin.read()
fin.close()

# send image to vps module
ret = vps.set_img(img)

【Return Value】

Return Value	Description
0	Success
-1	Failure

【Notes】

This API must be called after open_vps.

【Reference Code】

import sys, os, time

import numpy as np
import cv2
from hobot_vio import libsrcampy

def test_camera_vps():
    vps = libsrcampy.Camera()

    # enable vps function, input: 1080p, output: 512x512
    ret = vps.open_vps(1, 1, 1920, 1080, 512, 512)
    print("Camera vps return:%d" % ret)

    fin = open("output.img", "rb")
    img = fin.read()
    fin.close()

    # send image data to vps
    ret = vps.set_img(img)
    print ("Process set_img return:%d" % ret)

    fo = open("output_vps.img", "wb+")

    # get image data from vps
    img = vps.get_img()
    if img is not None:
        fo.write(img)
        print("encode write image success")
    else:
        print("encode write image failed")
    fo.close()

    # close vps function
    vps.close_cam()
    print("test_camera_vps done!!!")

test_camera_vps()

close_cam

【Function Description】

Disable the enabled MIPI camera.

【Function Declaration】

Camera.close_cam()

【Parameter Description】

None

【Usage】

cam = libsrcampy.Camera()

# open MIPI camera, fps: 30, resolution: 1080p
ret = cam.open_cam(0, 1, 30, 1920, 1080)
print("Camera open_cam return:%d" % ret)

# close MIPI camera
cam.close_cam()

【Return Value】

None

【Notes】

None

【Reference Code】

None

Host ID Selection

The host ID corresponding to the camera is shown in the figure below:

open_cam​

open_vps​

get_img​

set_img​

close_cam​

Host ID Selection​

open_cam

open_vps

get_img

set_img

close_cam

Host ID Selection