Difference between revisions of "Team:NAWI Graz/FlourescenceChamber"

Line 37: Line 37:
 
     </div>
 
     </div>
 
</div>
 
</div>
 +
 +
  
 
     <div class="section container">
 
     <div class="section container">
Line 46: Line 48:
 
         </div>
 
         </div>
 
     </div>
 
     </div>
 +
 +
<div class="section container">
 +
        <h2 class="section-sub">UV-Cuvette Compartment</h2>
 +
        <div class="section-text container">
 +
            <p>A UV-permissible quartz cuvette modified such as to connect to tubes on both ends to allow for the controlled transition of bacterial suspension.</p>
 +
        </div>
 +
    </div>
 +
  
 
     <div class="section container">
 
     <div class="section container">

Revision as of 23:27, 1 November 2017

FLOURESCENCE MEASUREMENT CHAMBER

A 3D printed case housing a cuvette (with in- and outflow tubes), LEDs to excite the fluorescent proteins, optical filters and two camera-modules. We look into the raw RGB data in a region of interest to detect bacterial fluorescence. The information from both cameras is aggregated into a single output: the next command to the robot.

The image cannot be displayed
Fig. 1: Overview of all parts constituting the fluorescence measurement chamber. See detailed description of all parts below.

Casing

The chamber is a two-part 3D-printed enclosure (see Fig. 2) with two facing walls housing sockets for LEDs that are all directed towards the center of the chamber. The outer two LED sockets of each row of three are oriented diagonally, their convergence in the interior can be seen in the bottom part of Fig. 2. The other two facing walls each contain one socket for a camera. If the two parts are plugged together, a rectangular tunnel passes through the chamber, leaving just enough space for the UV-cuvette and the placement of optical filters on each side.

The image cannot be displayed
Fig. 2: The two parts of the casing are shown from two different perspectives.

LEDs and Optical Filters

because of the expressed fluorescent protein’s spectral characteristics [explain shortly and link to molbio parts], we employ [XXX] nm LEDs to excite [XXX/proteins/chromophores?] and filter… images of LED’s emission spectrum and filter’s absorption curves for temperature experiment… ???

UV-Cuvette Compartment

A UV-permissible quartz cuvette modified such as to connect to tubes on both ends to allow for the controlled transition of bacterial suspension.

Function

After having passed an interaction module Bacterial suspension is transferred into the UV-cuvette in the interior of the chamber.

In the current setup, we only placed three [XXX UV?] LEDs in one wall. The other two opposing walls host camera sockets, to one one of which we have attached a RPi-camera, that is controlled by the RPi server. Two optical filters are placed inside. A [XXX] filter [do we show their spectral characteristics?] between the UV-LEDs and the cuvette, to filter out wavelengths from [XX] to [XX] nm (peak activation of eGFP at ~ XX nm). Between the cuvette and the camera a [XX] filter is inserted to allow only light emitted from activated bacteria through while holding back the rest of the LED-light.
The camera is controlled via the Python picamera library and calibrated to maximize the difference between idle and activated bacteria @allFromHof: (see table “camera-settings” or Supplemental Stuff, Zenodo, or nowhere?). The raw RGB-data is recorded, the green channel is kept and cropped to our region of interest---the bacterial suspension. The median green intensity of this region is then compared to a threshold [XX] to decipher the bacterial command.
The image cannot be displayed
Fig. 3: A view of the assembled fluorescence measurement chamber with LEDs emitting blue light. The white ribbon cable at the bottom of the module indicates the connection to the second camera.

Camera

… see “colicam_nu.py” on github/daniel_moser/colibot/server/cam/ … 1 second shutterspeed..

Software

Camera Master:
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
#!/usr/bin/env python
"""
Code for the master-camera.

It is connected to the slave-camera via 2 GPIO pins
and outputs the total detected bacterial state (aggregated
from both cameras).

@author: Daniel Hofstadler, 2017
"""
import os
import csv
import time
import argparse
import gpiozero
from datetime import datetime
from fractions import Fraction

import numpy as np
import picamera
import picamera.array

from matplotlib import pyplot as plt

# import warnings
# warnings.filterwarnings('error', category=DeprecationWarning)

# globals
# LOCAL_TZ = pytz.timezone("Etc/UTC")  # read from cams.csv
OUT_APPEND = "_coli"
CSV_NAME = "colicam"
CSV_HEADER = ["framerate", "exposure_time_us", "iso",
              "g1", "g2", "g3", "g4",
              "timestamp", "time_utc", "tag",
              "red", "green", "blue"]
# RESOLUTION = (2592, 1944)
RESOLUTION = (1280, 720)
# REGION_OF_INTEREST = (0.35, 0.4, 0.5, 0.7)
ROI = [200, 520, 480, 800]  # Y0, Y1, X0, X1
DETECTION_THRESHOLD = 150
PIN_RX = 17
PIN_TX = 18

SETTINGS_FIXED = {
        'name': "fixed",
        'ss': 1000000,  # 1000 milliseconds = 1 sec
        'fps': Fraction(1, 2),  # (1, 2)
        'iso': 800,  # 800
        'g': (Fraction(2, 1), Fraction(1, 1)),
        # 'g': (Fraction(345, 256), Fraction(167, 128)),
        'sleep': 15}  # 10
SETTINGS_SENSITIVE = {
        'name': "sensitive",
        'ss': 6000000,  # 6 seconds
        'fps': Fraction(1, 6),
        'iso': 800,
        'g': None,
        'sleep': 30}
SETTINGS_AUTO = {
        'name': "auto",
        'ss': None,
        'fps': 30,
        'iso': 0,
        'g': None,
        'sleep': 2}

SETTINGS_DEFAULT = "fixed"

# argument parsing
parser = argparse.ArgumentParser(
        description="Colibot Photometer Camera.")
parser.add_argument("-d", "--debug", action="store_true",
                    help="debug mode")
parser.add_argument("-m", "--mode", type=str, default="fixed",
                    choices=["f", "fixed", "s", "sensitive", "a", "auto"],
                    help="set the camera mode")
parser.add_argument("-p", "--postfix", type=str, default="",
                    help="add string to filename")
# args = vars(ap.parse_args())
args = parser.parse_args()
if not args.postfix == "" and not args.postfix.startswith("_"):
    args.postfix = "_" + args.postfix


def now_str(pattern="_%y%m%d-%H%M%S_utc"):
    # return time.strftime(pattern, time.gmtime())
    return datetime.utcnow().strftime(pattern)


def from_timestamp(ts, pattern="%y%m%d-%H%M%S_utc"):
    return datetime.utcfromtimestamp(ts).strftime(pattern)


def safename(s, s_type):
    """Check whether a given file or folder 's' exists, return a non-existing
    filename.
    s ........ (full) filename or directory
    s_type ... 'file' or 'f' for files,
               'directory' or 'dir' or 'd' for folders
    Returns a file- or pathname that is supposedly safe to save
    without overwriting data.
    """
    low_type = str.lower(s_type)
    if low_type == 'file' or low_type == 'f':
        if os.path.isfile(s):
            s2 = s.split('.')
            s_base = s2[0]
            s_ext = s2[-1]

            counter = 0
            while os.path.isfile(s):
                s = s_base + "-{:02d}.".format(counter) + s_ext
                counter += 1

    elif low_type == 'directory' or low_type == 'dir' or low_type == 'd':
        if os.path.isdir(s):
            s_base = s

            counter = 0
            while os.path.isdir(s):
                s = s_base + "-{:02d}".format(counter)
                counter += 1
    return s


class ColiCamMaster:
    global RESOLUTION
    global ROI  # REGION_OF_INTEREST
    global DETECTION_THRESHOLD
    global SETTINGS_FIXED
    global SETTINGS_SENSITIVE
    global SETTINGS_AUTO
    global DEF_SETTINGS_NAME
    global PIN_RX
    global PIN_TX

    def __init__(self, resolution=RESOLUTION, mode=DEF_SETTINGS_NAME):
        try:
            self.cam = picamera.PiCamera(resolution=resolution)
            self.set_cam(mode)
        except Exception as err:
            self.cam = ""
            print("couldn't initialize camera, error: {}".format(err))
        self.rx = gpiozero.InputDevice(PIN_RX)
        self.tx = gpiozero.OutputDevice(PIN_TX)

    def set_cam(self, mode="fixed"):

        if mode.lower().startswith("f"):
            settings = SETTINGS_FIXED
        elif mode.lower().startswith("s"):
            settings = SETTINGS_SENSITIVE
        elif mode.lower().startswith("a"):
            settings = SETTINGS_AUTO
        else:
            print("wrong camera mode")

        # switch on auto mode
        self.cam.awb_mode = 'auto'
        self.cam.exposure_mode = 'auto'

        # settings = dict with fields: name, ss, fps, iso, g, sleep
        self.cam.framerate = settings['fps']
        if settings['ss']:
            self.cam.shutter_speed = settings['ss']
        self.cam.iso = settings['iso']

        # Wait for the automatic gain control to settle
        time.sleep(settings['sleep'])

        # Now fix the values
        if not settings['ss']:
            self.cam.shutter_speed = self.cam.exposure_speed
        self.cam.exposure_mode = 'off'

        if settings['g']:
            g = settings['g']
        else:
            g = self.cam.awb_gains
        self.cam.awb_mode = 'off'
        self.cam.awb_gains = g

    def measure(self,
                roi=ROI,
                channel_name="green",
                threshold=DETECTION_THRESHOLD,
                dir_out=None,
                csv_out=None,
                postfix=""):

        # notify other camera to take a picture
        self.tx.on()

        # check whether channel is valid
        if channel_name.lower().startswith("r"):
            channel = 0
            channel_name = "red"
        elif channel_name.lower().startswith("g"):
            channel = 1
            channel_name = "green"
        elif channel_name.lower().startswith("b"):
            channel = 2
            channel_name = "blue"
        else:
            print("wrong channel_name: '{}'".format(channel_name))

        # get camera settings
        time.sleep(1)
        fps = float(self.cam.framerate)
        ss = self.cam.exposure_speed
        g = self.cam.awb_gains
        g1 = g[0].numerator
        g2 = g[0].denominator
        g3 = g[1].numerator
        g4 = g[1].denominator
        iso = self.cam.iso
        settings_str = "ss{}_g{}-{}_{}-{}_iso{}_".format(
                ss, g1, g2, g3, g4, iso)
        csv_row = [fps, ss, iso, g1, g2, g3, g4]
        print("taking photos with settings: {}".format(
                settings_str))

        # with picamera.PiCamera(resolution=RESOLUTION) as cam:
        # https://picamera.readthedocs.io/en/latest/
        #         api_array.html#module-picamera.array
        with picamera.array.PiRGBArray(self.cam) as output:

            # cam.zoom = REGION_OF_INTEREST
            # cam.start_preview()

            # take picture
            t0 = time.time()
            self.cam.capture(output, format="rgb")
            a = output.array
            t1 = time.time()
            print("recorded for {} sec".format(round(t1-t0, 2)))
            t_pic = int(round(np.mean([t0, t1])))
            # re-empty output (to reuse next iteration)
            # output.truncate(0)

        # crop to region of interest
        roi = a[ROI[0]:ROI[1], ROI[2]:ROI[3], :]

        vals = []
        vals.append(np.median(roi[:, :, 0]))
        vals.append(np.median(roi[:, :, 1]))
        vals.append(np.median(roi[:, :, 2]))

        print(("roi.shape={},\n" +
               # "sum(red)={}, sum(green)={}, sum(blue)={},\n" +
               "med(red)={}, med(green)={}, med(blue)={}").format(
                       roi.shape, vals[0], vals[1], vals[2]))

        val = vals[channel]
        print("reading the {} channel...\nvalue: {}".format(
                channel_name, val))
        if val >= threshold:
            activated = True
        else:
            activated = False
        print("active={} (threshold: {})".format(activated, threshold))

        # debug mode:
        # output images and csv if output directory exists
        if dir_out:

            names = ["1-red", "2-green", "3-blue"]

            # whole images
            fn = "full_{}{}_0-rgb{}.png".format(
                    settings_str, postfix, now_str())
            ffn = safename(os.path.join(dir_out, fn), "file")
            plt.imsave(ffn, a)
            for i in range(3):
                fn = "full_{}{}_{}{}.png".format(
                        settings_str, postfix,
                        names[i], now_str())
                ffn = safename(os.path.join(dir_out, fn), "file")
                plt.imsave(ffn, a[:, :, i], vmin=0, vmax=255)

            # cropped to ROI
            fn = "roi_{}{}_0-rgb{}.png".format(
                    settings_str, postfix, now_str())
            ffn = safename(os.path.join(dir_out, fn), "file")
            plt.imsave(ffn, roi)
            for i in range(3):
                fn = "roi_{}{}_{}{}.png".format(
                        settings_str, postfix,
                        names[i], now_str())
                ffn = safename(os.path.join(dir_out, fn), "file")
                plt.imsave(ffn, roi[:, :, i], vmin=0, vmax=255)

            csv_row.extend([t_pic, from_timestamp(t_pic), postfix,
                            vals[0], vals[1], vals[2]])
            with open(csv_out, "at") as csvfile:
                csvwriter = csv.writer(csvfile)
                csvwriter.writerow(csv_row)
            print("wrote csv_row: {}".format(csv_row))

        # read state of the slave-camera
        other_activated = False
        # impossible that both are active!
        if not activated:
            timeout = time.time() + 2  # seconds
            while not other_activated and time.time() < timeout:
                other_activated = self.rx.is_active
        self.tx.off()

        # determine final state
        if activated:
            output = 1
        elif other_activated:
            output = -1
        else:
            output = 0

        return output

    def exit_clean(self):
        if not self.cam == "":
            self.cam.close()


def main(args):
    global CSV_NAME
    global CSV_HEADER

    # t0 = time.time()
    cam = ColiCamMaster(mode=args.mode)
    # t_cam = time.time() - t0

    # select mode (camera settings)
    current_mode = args.mode

    # optionally create output directory for debugging
    if args.debug:
        # setup output directory (and copy over the code?)
        dir_out = "/home/pi/ColiCam_{}".format(now_str("%y%m%d"))
        dir_out = safename(dir_out, "dir")
        if not os.path.isdir(dir_out):
            os.mkdir(dir_out)
        print("outputting to '{}'".format(dir_out))
        # initialize csv-log
        csv_fn = "{}{}{}.csv".format(CSV_NAME, args.postfix, now_str())
        csv_out = safename(os.path.join(dir_out, csv_fn), 'file')
        # write header
        with open(csv_out, "wt") as csvfile:
            csvwriter = csv.writer(csvfile)
            csvwriter.writerow(CSV_HEADER)
        print("initialized {} with header {}".format(
                csv_out, CSV_HEADER))
    else:
        dir_out = None
        csv_out = None

    # it = 0
    try:
        while True:
            # it += 1

            # update mode
            new_mode = args.mode
            if not current_mode == new_mode:
                cam.set_cam(mode=new_mode)
            # cam.set_cam(mode=args.mode)
            print("measuring in {} mode (default):".format(args.mode))

            # measure with both cams
            val = cam.measure(dir_out=dir_out, csv_out=csv_out,
                              postfix=args.postfix)
            if val == -1:
                print("wall on the left\n")
            elif val == 0:
                print("no wall detected\n")
            elif val == 1:
                print("wall on the right\n")

    except KeyboardInterrupt:
        print("manually interrupted program")

    finally:
        cam.exit_clean()
        print("camera closed, done!")


if __name__ == "__main__":
    main(args)

Camera Slave:
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
#!/usr/bin/env python
"""
Code for the slave-camera

It is connected to the master-camera via 2 GPIO pins
and outputs the detected bacterial state via the
GPIO-connection to the master-camera.

In order to constantly listen for commands from the
master camera, it needs to start a background-
thread.

@author: Daniel Hofstadler, 2017
"""
import os
import csv
import time
import argparse
import gpiozero
import threading
from datetime import datetime
from fractions import Fraction

import numpy as np
import picamera
import picamera.array

from matplotlib import pyplot as plt

# import warnings
# warnings.filterwarnings('error', category=DeprecationWarning)

# globals
# LOCAL_TZ = pytz.timezone("Etc/UTC")  # read from cams.csv
OUT_APPEND = "_coli"
CSV_NAME = "colicam"
CSV_HEADER = ["framerate", "exposure_time_us", "iso",
              "g1", "g2", "g3", "g4",
              "timestamp", "time_utc", "tag",
              "red", "green", "blue"]
# RESOLUTION = (2592, 1944)
RESOLUTION = (1280, 720)
# REGION_OF_INTEREST = (0.35, 0.4, 0.5, 0.7)
ROI = [200, 520, 480, 800]  # Y0, Y1, X0, X1
DETECTION_THRESHOLD = 150
PIN_RX = 17
PIN_TX = 18

SETTINGS_FIXED = {
        'name': "fixed",
        'ss': 1000000,  # 1000 milliseconds = 1 sec
        'fps': Fraction(1, 2),  # (1, 2)
        'iso': 800,  # 800
        'g': (Fraction(2, 1), Fraction(1, 1)),
        # 'g': (Fraction(345, 256), Fraction(167, 128)),
        'sleep': 15}  # 10
SETTINGS_SENSITIVE = {
        'name': "sensitive",
        'ss': 6000000,  # 6 seconds
        'fps': Fraction(1, 6),
        'iso': 800,
        'g': None,
        'sleep': 30}
SETTINGS_AUTO = {
        'name': "auto",
        'ss': None,
        'fps': 30,
        'iso': 0,
        'g': None,
        'sleep': 2}

SETTINGS_DEFAULT = "fixed"

# argument parsing
parser = argparse.ArgumentParser(
        description="Colibot Photometer Camera.")
parser.add_argument("-d", "--debug", action="store_true",
                    help="debug mode")
parser.add_argument("-m", "--mode", type=str, default="fixed",
                    choices=["f", "fixed", "s", "sensitive", "a", "auto"],
                    help="set the camera mode")
parser.add_argument("-p", "--postfix", type=str, default="",
                    help="add string to filename")
# args = vars(ap.parse_args())
args = parser.parse_args()
if not args.postfix == "" and not args.postfix.startswith("_"):
    args.postfix = "_" + args.postfix


def now_str(pattern="_%y%m%d-%H%M%S_utc"):
    # return time.strftime(pattern, time.gmtime())
    return datetime.utcnow().strftime(pattern)


def from_timestamp(ts, pattern="%y%m%d-%H%M%S_utc"):
    return datetime.utcfromtimestamp(ts).strftime(pattern)


def safename(s, s_type):
    """Check whether a given file or folder 's' exists, return a non-existing
    filename.
    s ........ (full) filename or directory
    s_type ... 'file' or 'f' for files,
               'directory' or 'dir' or 'd' for folders
    Returns a file- or pathname that is supposedly safe to save
    without overwriting data.
    """
    low_type = str.lower(s_type)
    if low_type == 'file' or low_type == 'f':
        if os.path.isfile(s):
            s2 = s.split('.')
            s_base = s2[0]
            s_ext = s2[-1]

            counter = 0
            while os.path.isfile(s):
                s = s_base + "-{:02d}.".format(counter) + s_ext
                counter += 1

    elif low_type == 'directory' or low_type == 'dir' or low_type == 'd':
        if os.path.isdir(s):
            s_base = s

            counter = 0
            while os.path.isdir(s):
                s = s_base + "-{:02d}".format(counter)
                counter += 1
    return s


def thread_listener(cam):
    """Background thread listening on the receive-pin
    whether to make a measurement."""
    try:
        while cam.active:
            if cam.rx.is_active:
                cam.measure_slave()
            time.sleep(0.5)
    finally:
        print("listener thread shutting down")


class ColiCamSlave:
    global RESOLUTION
    global ROI  # REGION_OF_INTEREST
    global DETECTION_THRESHOLD
    global SETTINGS_FIXED
    global SETTINGS_SENSITIVE
    global SETTINGS_AUTO
    global DEF_SETTINGS_NAME
    global PIN_RX
    global PIN_TX

    def __init__(self, resolution=RESOLUTION, mode=DEF_SETTINGS_NAME):
        try:
            self.cam = picamera.PiCamera(resolution=resolution)
            self.set_cam(mode)
        except Exception as err:
            self.cam = ""
            print("couldn't initialize camera, error: {}".format(err))
        self.rx = gpiozero.InputDevice(PIN_RX)
        self.tx = gpiozero.OutputDevice(PIN_TX)
        self.active = True

        # start the listening thread
        listener = threading.Thread(
                target=thread_listener, args=(self))
        listener.daemon = True
        listener.start()
        self.listener = listener

    def set_cam(self, mode="fixed"):

        if mode.lower().startswith("f"):
            settings = SETTINGS_FIXED
        elif mode.lower().startswith("s"):
            settings = SETTINGS_SENSITIVE
        elif mode.lower().startswith("a"):
            settings = SETTINGS_AUTO
        else:
            print("wrong camera mode")

        # switch on auto mode
        self.cam.awb_mode = 'auto'
        self.cam.exposure_mode = 'auto'

        # settings = dict with fields: name, ss, fps, iso, g, sleep
        self.cam.framerate = settings['fps']
        if settings['ss']:
            self.cam.shutter_speed = settings['ss']
        self.cam.iso = settings['iso']

        # Wait for the automatic gain control to settle
        time.sleep(settings['sleep'])

        # Now fix the values
        if not settings['ss']:
            self.cam.shutter_speed = self.cam.exposure_speed
        self.cam.exposure_mode = 'off'

        if settings['g']:
            g = settings['g']
        else:
            g = self.cam.awb_gains
        self.cam.awb_mode = 'off'
        self.cam.awb_gains = g

    def measure_slave(self,
                      roi=ROI,
                      channel_name="green",
                      threshold=DETECTION_THRESHOLD,
                      dir_out=None,
                      csv_out=None,
                      postfix=""):

        # check whether channel is valid
        if channel_name.lower().startswith("r"):
            channel = 0
            channel_name = "red"
        elif channel_name.lower().startswith("g"):
            channel = 1
            channel_name = "green"
        elif channel_name.lower().startswith("b"):
            channel = 2
            channel_name = "blue"
        else:
            print("wrong channel_name: '{}'".format(channel_name))

        # get camera settings
        time.sleep(1)
        fps = float(self.cam.framerate)
        ss = self.cam.exposure_speed
        g = self.cam.awb_gains
        g1 = g[0].numerator
        g2 = g[0].denominator
        g3 = g[1].numerator
        g4 = g[1].denominator
        iso = self.cam.iso
        settings_str = "ss{}_g{}-{}_{}-{}_iso{}_".format(
                ss, g1, g2, g3, g4, iso)
        csv_row = [fps, ss, iso, g1, g2, g3, g4]
        print("taking photos with settings: {}".format(
                settings_str))

        # with picamera.PiCamera(resolution=RESOLUTION) as cam:
        # https://picamera.readthedocs.io/en/latest/
        #         api_array.html#module-picamera.array
        with picamera.array.PiRGBArray(self.cam) as output:

            # cam.zoom = REGION_OF_INTEREST
            # cam.start_preview()

            # take picture
            t0 = time.time()
            self.cam.capture(output, format="rgb")
            a = output.array
            t1 = time.time()
            print("recorded for {} sec".format(round(t1-t0, 2)))
            t_pic = int(round(np.mean([t0, t1])))
            # re-empty output (to reuse next iteration)
            # output.truncate(0)

        # crop to region of interest
        roi = a[ROI[0]:ROI[1], ROI[2]:ROI[3], :]

        vals = []
        vals.append(np.median(roi[:, :, 0]))
        vals.append(np.median(roi[:, :, 1]))
        vals.append(np.median(roi[:, :, 2]))

        print(("roi.shape={},\n" +
               # "sum(red)={}, sum(green)={}, sum(blue)={},\n" +
               "med(red)={}, med(green)={}, med(blue)={}").format(
                       roi.shape, vals[0], vals[1], vals[2]))

        val = vals[channel]
        print("reading the {} channel...\nvalue: {}".format(
                channel_name, val))

        # checking whether threshold is crossed and
        #   signalling the master-camera
        if val >= threshold:
            activated = True
            self.tx.on()
        else:
            activated = False
            self.tx.off()
        print("active={} (threshold: {})".format(activated, threshold))

        # debug mode:
        # output images and csv if output directory exists
        if dir_out:

            names = ["1-red", "2-green", "3-blue"]

            # whole images
            fn = "full_{}{}_0-rgb{}.png".format(
                    settings_str, postfix, now_str())
            ffn = safename(os.path.join(dir_out, fn), "file")
            plt.imsave(ffn, a)
            for i in range(3):
                fn = "full_{}{}_{}{}.png".format(
                        settings_str, postfix,
                        names[i], now_str())
                ffn = safename(os.path.join(dir_out, fn), "file")
                plt.imsave(ffn, a[:, :, i], vmin=0, vmax=255)

            # cropped to ROI
            fn = "roi_{}{}_0-rgb{}.png".format(
                    settings_str, postfix, now_str())
            ffn = safename(os.path.join(dir_out, fn), "file")
            plt.imsave(ffn, roi)
            for i in range(3):
                fn = "roi_{}{}_{}{}.png".format(
                        settings_str, postfix,
                        names[i], now_str())
                ffn = safename(os.path.join(dir_out, fn), "file")
                plt.imsave(ffn, roi[:, :, i], vmin=0, vmax=255)

            csv_row.extend([t_pic, from_timestamp(t_pic), postfix,
                            vals[0], vals[1], vals[2]])
            with open(csv_out, "at") as csvfile:
                csvwriter = csv.writer(csvfile)
                csvwriter.writerow(csv_row)
            print("wrote csv_row: {}".format(csv_row))

        return None

    def exit_clean(self):
        if not self.cam == "":
            self.cam.close()
        self.active = False
        self.listener.join()


def main(args):
    global CSV_NAME
    global CSV_HEADER

    # t0 = time.time()
    cam = ColiCamSlave(mode=args.mode)
    # t_cam = time.time() - t0

    # select mode (camera settings)
    current_mode = args.mode

    # optionally create output directory for debugging
    if args.debug:
        # setup output directory (and copy over the code?)
        dir_out = "/home/pi/ColiCam_{}".format(now_str("%y%m%d"))
        dir_out = safename(dir_out, "dir")
        if not os.path.isdir(dir_out):
            os.mkdir(dir_out)
        print("outputting to '{}'".format(dir_out))
        # initialize csv-log
        csv_fn = "{}{}{}.csv".format(CSV_NAME, args.postfix, now_str())
        csv_out = safename(os.path.join(dir_out, csv_fn), 'file')
        # write header
        with open(csv_out, "wt") as csvfile:
            csvwriter = csv.writer(csvfile)
            csvwriter.writerow(CSV_HEADER)
        print("initialized {} with header {}".format(
                csv_out, CSV_HEADER))
    else:
        dir_out = None
        csv_out = None

    # it = 0
    try:
        while True:
            # it += 1

            # update mode
            new_mode = args.mode
            if not current_mode == new_mode:
                cam.set_cam(mode=new_mode)
            # cam.set_cam(mode=args.mode)
            print("measuring in {} mode (default):".format(args.mode))

            # measure with both cams
            val = cam.measure(dir_out=dir_out, csv_out=csv_out,
                              postfix=args.postfix)
            if val == -1:
                print("wall on the left\n")
            elif val == 0:
                print("no wall detected\n")
            elif val == 1:
                print("wall on the right\n")

    except KeyboardInterrupt:
        print("manually interrupted program")

    finally:
        cam.exit_clean()
        print("camera closed, done!")


if __name__ == "__main__":
    main(args)