Convert Output Thermal Camera to RGB in OpenCV

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I'm working on Lepton 2.5. thermal camera. When I run the code below, the output is on greyscale (attached image 1)..

Maybe somebody can help me to adjust this code so the output will be a RGB color (attached image 2). I really appreciate the assistance given. Sorry if I am not very competent in python or opencv, I try my best.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from uvctypes import *
import time
import cv2
import numpy as np
try:
  from queue import Queue
except ImportError:
  from Queue import Queue
import platform

BUF_SIZE = 2
q = Queue(BUF_SIZE)

def py_frame_callback(frame, userptr):

  array_pointer = cast(frame.contents.data, POINTER(c_uint16 * (frame.contents.width * frame.contents.height)))
  data = np.frombuffer(
    array_pointer.contents, dtype=np.dtype(np.uint16)
  ).reshape(
    frame.contents.height, frame.contents.width
  ) # no copy

  # data = np.fromiter(
  #   frame.contents.data, dtype=np.dtype(np.uint8), count=frame.contents.data_bytes
  # ).reshape(
  #   frame.contents.height, frame.contents.width, 2
  # ) # copy

  if frame.contents.data_bytes != (2 * frame.contents.width * frame.contents.height):
    return

  if not q.full():
    q.put(data)

PTR_PY_FRAME_CALLBACK = CFUNCTYPE(None, POINTER(uvc_frame), c_void_p)(py_frame_callback)

def ktof(val):
  return (1.8 * ktoc(val) + 32.0)

def ktoc(val):
  return (val - 27315) / 100.0

def raw_to_8bit(data):
  cv2.normalize(data, data, 0, 65535, cv2.NORM_MINMAX)
  np.right_shift(data, 8, data)
  return cv2.cvtColor(np.uint8(data), cv2.COLOR_GRAY2RGB)

def display_temperature(img, val_k, loc, color):
  val = ktoc(val_k) #select between ktoc or ktof
  cv2.putText(img,"{0:.1f} Celcius".format(val), loc, cv2.FONT_HERSHEY_SIMPLEX, 0.75, color, 2)
  x, y = loc
  cv2.line(img, (x - 2, y), (x + 2, y), color, 1)
  cv2.line(img, (x, y - 2), (x, y + 2), color, 1)

def main():
  ctx = POINTER(uvc_context)()
  dev = POINTER(uvc_device)()
  devh = POINTER(uvc_device_handle)()
  ctrl = uvc_stream_ctrl()

  res = libuvc.uvc_init(byref(ctx), 0)
  if res < 0:
    print("uvc_init error")
    exit(1)

  try:
    res = libuvc.uvc_find_device(ctx, byref(dev), PT_USB_VID, PT_USB_PID, 0)
    if res < 0:
      print("uvc_find_device error")
      exit(1)

    try:
      res = libuvc.uvc_open(dev, byref(devh))
      if res < 0:
        print("uvc_open error")
        exit(1)

      print("device opened!")
# device format
      print_device_info(devh)
      print_device_formats(devh)

      frame_formats = uvc_get_frame_formats_by_guid(devh, VS_FMT_GUID_Y16)
      if len(frame_formats) == 0:
        print("device does not support Y16")
        exit(1)

      libuvc.uvc_get_stream_ctrl_format_size(devh, byref(ctrl), UVC_FRAME_FORMAT_Y16,
        frame_formats[0].wWidth, frame_formats[0].wHeight, int(1e7 / frame_formats[0].dwDefaultFrameInterval)
      )

      res = libuvc.uvc_start_streaming(devh, byref(ctrl), PTR_PY_FRAME_CALLBACK, None, 0)
      if res < 0:
        print("uvc_start_streaming failed: {0}".format(res))
        exit(1)

      try:
        while True:
          data = q.get(True, 500)
          if data is None:
            break
          data = cv2.resize(data[:,:], (640, 480))
          minVal, maxVal, minLoc, maxLoc = cv2.minMaxLoc(data)
          img = raw_to_8bit(data)
          display_temperature(img, minVal, minLoc, (255, 0, 0))
          display_temperature(img, maxVal, maxLoc, (0, 0, 255))
          cv2.imshow('Lepton Radiometry', img)
          if cv2.waitKey(1) & 0xFF == ord('q'):
            break

        cv2.destroyAllWindows()
      finally:
        libuvc.uvc_stop_streaming(devh)

      print("done")
    finally:
      libuvc.uvc_unref_device(dev)
  finally:
    libuvc.uvc_exit(ctx)

if __name__ == '__main__':
  main()

This is the sample output of greyscale image This is the sample output of greyscale image with above code

This is the sample output of RGB image (with another code) This is the sample output of RGB image (with another code)

1

There are 1 answers

1
amisotcm On BEST ANSWER

Thanks to Peter Gibson You can find the answer on https://learnopencv.com/applycolormap-for-pseudocoloring-in-opencv-c-python/

you just have to take the latest image variable to show and redirect it into

im_color = cv2.applyColorMap(img, cv2.COLORMAP_JET)

and send it to cv2.imshow