DJI Thermal SDK

use ctypes to capsulate the DJI Thermal SDK so that we can directly use python to process thermal images.

from dji_thermal_sdk.dji_sdk import *
from dji_thermal_sdk.utility import rjpeg_to_heatmap, rjpeg_to_thermal
import dji_thermal_sdk.dji_sdk as DJI
import dji_thermal_sdk.utility as util
import ctypes as CT
from ctypes import *
import os,sys
import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns

This version of DJI Thermal SDK is 1.4, which was published on 11/09/2022

Install

pip install dji_thermal_sdk

The package only can work on Windows System.

For Windows OS, DJI SDK DLLs include libdirp.dll, libv_dirp.dll, libv_girp.dll, libv_iirp.dll, libv_list.ini.

For Linux OS, DJI SDK DLLs include libdirp.so, libv_dirp.so, libv_girp.so, libv_iirp.so, libv_list.ini.

Firstly, you should invoke ‘dji_init’ to initialize DJI sdk environment. This step is very important

Initialize the DJI environment. This step is very important

if you don’t provide the file path of ‘libdirp.dll’, the default ‘libdirp.dll’ with version 1.3 will be automatically chosen.

root = os.path.dirname(DJI.__file__)
if sys.platform.startswith('linux'):
    dllpath = os.path.join(root,'linux', 'libdirp.so')
    osname  = 'linux'
else:
    dllpath = os.path.join(root,'windows', 'libdirp.dll')
    osname  = 'windows'

if os.path.isfile(dllpath):
    print(f'current OS is {osname}, dllpath:{dllpath}')
else:
    print("please download SDK from https://www.dji.com/downloads/softwares/dji-thermal-sdk")
#

dji_init(dllpath=dllpath, osname=osname)
DJI._libdirp

current OS is linux, dllpath:/home/hxl170008/code/git_repos/dji_thermal_sdk/dji_thermal_sdk/linux/libdirp.so

<CDLL '/home/hxl170008/code/git_repos/dji_thermal_sdk/dji_thermal_sdk/linux/libdirp.so', handle 3f7c160 at 0x7facfbf1e6d0>

Get the handle of a R-JPEG image

DIRP_HANDLE is a void pointer, and it has been definded.
you can get it by package.DIRP_HANDLE

rd = r"dataset\Deer_Goats_Unsure.jpg"
with open(rd, 'rb') as f:
    content = f.read()
    print(len(content))
# method1 to get the file size
print(f"File size: {os.path.getsize(rd)}")
# method 2 to get the file size
file_stat = os.stat(rd)
size = c_int32(file_stat.st_size)
print(f"File size: {size}")

# the method to create a string buffer, which is important.
rjpeg_data = CT.create_string_buffer(len(content))
rjpeg_data.value = content
print(f"rjpeg_data: {rjpeg_data}")

# test the function to create a handle of an image
ret = dirp_create_from_rjpeg(rjpeg_data,size, CT.byref(DIRP_HANDLE))
print(f'ret = {ret}')
if ret == 0:
    print("successfully get the r-jpeg handle.")
#
print(f"DIRP_HANDLE: {DIRP_HANDLE}  address: {hex(DIRP_HANDLE.value)} ")

1367428
File size: 1367428
File size: c_long(1367428)
rjpeg_data: <ctypes.c_char_Array_1367428 object>
ret = 0
successfully get the r-jpeg handle.
DIRP_HANDLE: c_void_p(2201333297840)  address: 0x20089b072b0 

Get the version of API

jpeg_version = dirp_api_version_t() 
ret = dirp_get_api_version(CT.byref(jpeg_version))
if ret == DIRP_SUCCESS:
    print("Success")
#
print(f"jpeg_version.api: \t {jpeg_version.api}")
print(f"jpeg_version.magic: \t {jpeg_version.magic}")

Success
jpeg_version.api:    19
jpeg_version.magic:      b'b85e4d3'

Get the version of DJI JPG

jpeg_version = dirp_rjpeg_version_t()
ret = dirp_get_api_version(CT.byref(jpeg_version))
if ret == DIRP_SUCCESS:
    print("Success")
#
print(f"rjpeg:{jpeg_version.rjpeg}")
print(f"header:{jpeg_version.header}")
print(f"curve:{jpeg_version.curve}")

Success
rjpeg:19
header:1697986658
curve:3367988

Get Color Bar

nbdev.show_doc(dirp_color_bar_t)

class dirp_color_bar_t[source]

dirp_color_bar_t() :: Structure

Color bar parameters structure definition

jpeg_color_bar = dirp_color_bar_t()
ret = dirp_get_color_bar(DIRP_HANDLE, CT.byref(jpeg_color_bar))
if ret == DIRP_SUCCESS:
    print("Success")
print(f"jpeg_color_bar.high: \t {jpeg_color_bar.high}")
print(f"jpeg_color_bar.low: \t {jpeg_color_bar.low}")
print(f"jpeg_color_bar.manual_enable: \t {jpeg_color_bar.manual_enable}")

Success
jpeg_color_bar.high:     -131073.015625
jpeg_color_bar.low:      9.10844001811131e-44
jpeg_color_bar.manual_enable:    False

Get the resolution of a R-JPEG image

rjpeg_resolution = dirp_resolution_t()
ret = dirp_get_rjpeg_resolution(DIRP_HANDLE, CT.byref(rjpeg_resolution))
print(f'ret = {ret}')
if ret == 0:
    print("successfully get the resolution.")

out = f'Height: {rjpeg_resolution.height}, width: {rjpeg_resolution.width}'
out

ret = 0
successfully get the resolution.

'Height: 512, width: 640'

Set Pseudo Color

• DIRP_PSEUDO_COLOR_WHITEHOT = 0
• DIRP_PSEUDO_COLOR_FULGURITE = 1
• DIRP_PSEUDO_COLOR_IRONRED = 2
• DIRP_PSEUDO_COLOR_HOTIRON = 3
• DIRP_PSEUDO_COLOR_MEDICAL = 4
• DIRP_PSEUDO_COLOR_ARCTIC = 5
• DIRP_PSEUDO_COLOR_RAINBOW1 = 6
• DIRP_PSEUDO_COLOR_RAINBOW2 = 7
• DIRP_PSEUDO_COLOR_TINT = 8
• DIRP_PSEUDO_COLOR_BLACKHOT = 9

ret = dirp_set_pseudo_color(DIRP_HANDLE, c_int(0))
if ret == DIRP_SUCCESS:
    print("Success")
else:
    print(f"Error: ret={ret}")

Success

Transform a thermal image by a specific palette

size = rjpeg_resolution.height * rjpeg_resolution.width * 3 * CT.sizeof(c_uint8)
raw_image_buffer = CT.create_string_buffer(size)
print(raw_image_buffer.raw[100])
ret = dirp_process(DIRP_HANDLE,byref(raw_image_buffer), size)
if ret == DIRP_SUCCESS:
    print("Success")
else:
    print(f"Error: ret={ret}")
#
raw_file_path = os.path.splitext(rd)[0] + ".raw"
print(raw_file_path)
with open(raw_file_path, 'wb') as f:
    f.write(raw_image_buffer.raw)
#
if os.path.exists(raw_file_path):
    print(f"Success! file size: {os.path.getsize(raw_file_path)}")
else:
    print("Error")
#
with open(raw_file_path, encoding='cp1252') as fin:
    img = np.fromfile(fin, dtype = np.uint8)
    print(img.shape)
    img.shape = (512,640,3)
    #original = Image.fromarray(img)
#

fig = plt.figure(figsize=(10,8))
plt.imshow(img, cmap='gray')

rjpge_to_thermal

if DJI._libdirp == "":
    print("run dji_init() to initialize the DJI sdk.")
src = r"dataset\Deer_Goats_Unsure.jpg"
img = rjpeg_to_thermal(src,0)
fig = plt.figure(figsize=(10,8))
plt.imshow(img)
plt.show()

img = rjpeg_to_thermal(src,2)
fig = plt.figure(figsize=(5,4))
plt.imshow(img)
plt.show()

rjpge_to_heatmap

if DJI._libdirp == "":
    print("run dji_init() to initialize the DJI sdk.")
src = r"dataset\Deer_Goats_Unsure.jpg"
img = rjpeg_to_heatmap(src,dtype='float32')
fig = plt.figure(figsize=(10,8))
ax = sns.heatmap(img, cmap='gray')
ax.set_xticks([])
ax.set_yticks([])
plt.show()

if DJI._libdirp == "":
    print("run dji_init() to initialize the DJI sdk.")
src = r"dataset\Deer_Goats_Unsure.jpg"
img = rjpeg_to_heatmap(src,dtype='int16')
fig = plt.figure(figsize=(10,8))
ax = sns.heatmap(img, cmap='gray')
ax.set_xticks([])
ax.set_yticks([])
plt.show()