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NONAI2D CSC Module API Manual

Overview

The K230 chip has 24 built-in hardware Color Space Conversion (CSC) channels, capable of efficiently performing image color space conversion processing. This module supports multiple image format conversions, including common formats such as RGB/YUV, and is suitable for scenarios such as video processing and image display.

API Reference

Constructor

Function Initializes the CSC conversion channel. The channel number is automatically allocated by the system, with no need for the user to specify.

Syntax

from nonai2d import CSC
csc = CSC(fmt, max_width=1920, max_height=1080, buf_num=2)

Parameter Description

Parameter	Type	Description	Default
fmt	int	Target image format (see constant definitions)	None
max_width	int	Maximum image width supported for processing (pixels)	1920
max_height	int	Maximum image height supported for processing (pixels)	1080
buf_num	int	Number of VB buffers allocated, affecting processing performance	2

Return Value Returns a CSC object on success, throws an exception on failure

Important Notes

1. The channel number is automatically allocated by the system (within the range 0-23), and the user neither needs to nor can specify it

2. It is recommended to set max_width/max_height according to the actual image size to save memory

3. When fmt=PIXEL_FORMAT_GRAYSCALE, it will first be internally converted to YUV420SP before extracting the grayscale channel

Properties

Property	Type	Description
chn	int	System-allocated CSC channel number
dst_fmt	int	Target image format

convert Method

Function Performs image color space conversion

Syntax

result = csc.convert(frame, timeout_ms=1000, cvt=True)

Parameter Description

Parameter	Type	Description	Default
frame	py_video_frame_info	Input image frame (obtained from Sensor.snapshot)	None
timeout_ms	int	Conversion timeout duration (milliseconds)	1000
cvt	bool	True returns Image object, False returns py_video_frame_info	True

Return Value Returns the converted Image object or py_video_frame_info based on the cvt parameter

get_frame Method

Function Retrieves the converted frame from the CSC channel (low-level interface, does not automatically convert to Image).

Syntax

frame = csc.get_frame(timeout_ms=1000)

Parameter Description

Parameter	Type	Description	Default
timeout_ms	int	Timeout duration (milliseconds)	1000

Return Value Returns a py_video_frame_info object on success, returns None on timeout

Note: Frames obtained using get_frame need to be manually released by calling release_frame.

release_frame Method

Function Releases a frame obtained via get_frame.

Syntax

csc.release_frame(frame)

Parameter Description

Parameter	Type	Description
frame	py_video_frame_info	The frame object to be released

destroy Method

Function Releases CSC channel resources

Syntax

csc.destroy()

Description After being called, all resources occupied by this CSC channel will be released, and the object can no longer be used

Constant Definitions

Image Format Constants

Constant Name	Description	Typical Application Scenarios
PIXEL_FORMAT_GRAYSCALE	Grayscale image format	Black and white image processing
PIXEL_FORMAT_RGB_565	RGB565 format (big-endian)	LCD display
PIXEL_FORMAT_RGB_565_LE	RGB565 format (little-endian)	Special display devices
PIXEL_FORMAT_BGR_565	BGR565 format (big-endian)	OpenCV compatible processing
PIXEL_FORMAT_BGR_565_LE	BGR565 format (little-endian)	Special display devices
PIXEL_FORMAT_RGB_888	RGB888 format	High-quality image processing
PIXEL_FORMAT_BGR_888	BGR888 format	OpenCV compatible processing
PIXEL_FORMAT_ARGB_8888	ARGB8888 format (with transparency)	Graphical interface composition
PIXEL_FORMAT_ARGB_1555	ARGB1555 format (with transparency)	Low color depth UI
PIXEL_FORMAT_ARGB_4444	ARGB4444 format (with transparency)	Low color depth UI
PIXEL_FORMAT_BGR_888_PLANAR	BGR888 planar format	Professional image processing
PIXEL_FORMAT_RGB_888_PLANAR	RGB888 planar format	Professional image processing
PIXEL_FORMAT_YVU_PLANAR_420	YVU420 planar format	Video decoding output
PIXEL_FORMAT_YUV_SEMIPLANAR_420	YUV420 semi-planar format	Video encoding input
PIXEL_FORMAT_YVU_SEMIPLANAR_420	YVU420 semi-planar format	Video processing
PIXEL_FORMAT_YVU_PLANAR_444	YVU444 planar format	High-quality video processing
PIXEL_FORMAT_YUV_PACKAGE_444	YUV444 packed format	High-quality video processing
PIXEL_FORMAT_YUV_SEMIPLANAR_444	YUV444 semi-planar format	High-quality video processing
PIXEL_FORMAT_YVU_SEMIPLANAR_444	YVU444 semi-planar format	High-quality video processing

Best Practice

import time, os, urandom, sys

from media.display import *
from media.media import *
from media.uvc import *

from nonai2d import CSC

DISPLAY_WIDTH = ALIGN_UP(800, 16)
DISPLAY_HEIGHT = 480

# hardware Color Space Converter (通道号自动分配)
csc = CSC(CSC.PIXEL_FORMAT_RGB_565)

# use lcd as display output
Display.init(Display.ST7701, width = DISPLAY_WIDTH, height = DISPLAY_HEIGHT, to_ide = True)

while True:
    plugin, dev = UVC.probe()
    if plugin:
        print(f"detect USB Camera {dev}")
        break
    time.sleep_ms(100)

mode = UVC.video_mode(640, 480, UVC.FORMAT_MJPEG, 30)

succ, mode = UVC.select_video_mode(mode)
print(f"select mode success: {succ}, mode: {mode}")

UVC.start(cvt = True)

clock = time.clock()

while True:
    clock.tick()

    img = UVC.snapshot()
    if img is not None:
        img = csc.convert(img)
        Display.show_image(img)

    print(clock.fps())

# deinit display
Display.deinit()
csc.destroy()
UVC.stop()

time.sleep_ms(100)