Added test images and some initial code.

PacketTX.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+#
+# Serial Packet Transmitter Class
+#
+# Frames packets (preamble, unique word, checksum)
+# and transmits them out of a serial port.
+#
+# Mark Jessop <vk5qi@rfhead.net>
+#
+
+
+import serial,Queue,sys,crcmod,struct
+from time import sleep
+from threading import Thread
+import numpy as np
+
+class BinaryDebug(object):
+	def __init__(self):
+		self.f = open("debug.bin",'wb')
+
+	def write(self,data):
+		# TODO: Add in RS232 framing
+		raw_data = np.array([],dtype=np.uint8)
+		for d in data:
+			d_array = np.unpackbits(np.fromstring(d,dtype=np.uint8))
+			raw_data = np.concatenate((raw_data,[0],d_array[::-1],[1]))
+
+		self.f.write(raw_data.astype(np.uint8).tostring())
+
+	def close(self):
+		self.f.close()
+
+
+class PacketTX(object):
+	txqueue = Queue.Queue(4096) # Up to 1MB of 256 byte packets
+	transmit_active = False
+	debug = False
+
+	unique_word = "\xab\xcd"
+	preamble = "\x55"*16
+	idle_sequence = "\x55"*256
+
+
+	def __init__(self,serial_port="/dev/ttyAMA0", serial_baud=115200, payload_length=256, debug = False):
+
+		if debug == True:
+			self.s = BinaryDebug()
+			self.debug = True
+		else:
+			self.s = serial.Serial(serial_port,serial_baud)
+		self.payload_length = payload_length
+
+		self.crc16 = crcmod.predefined.mkCrcFun('crc-ccitt-false')
+
+	def start_tx(self):
+		self.transmit_active = True
+		txthread = Thread(target=self.tx_thread)
+		txthread.start()
+
+	def frame_packet(self,packet):
+		# Ensure payload size is equal to the desired payload length
+		if len(packet) > self.payload_length:
+			packet = packet[:self.payload_length]
+
+		if len(packet) < self.payload_length:
+			packet = packet + "\x00"*(self.payload_length - len(packet))
+
+		crc = struct.pack("<H",self.crc16(packet))
+		return self.preamble + self.unique_word + packet + crc 
+
+
+	def tx_thread(self):
+		while self.transmit_active:
+			if self.txqueue.qsize()>0:
+				packet = self.txqueue.get_nowait()
+				self.s.write(packet)
+			else:
+				if not self.debug:
+					self.s.write(self.idle_sequence)
+				else:
+					sleep(0.05)
+		
+		print("Closing Thread")
+		self.s.close()
+
+	def close(self):
+		self.transmit_active = False
+
+	def wait(self):
+		while not self.txqueue.empty():
+			sleep(0.01)
+
+	def tx_packet(self,packet,blocking = False):
+		self.txqueue.put(self.frame_packet(packet))
+
+		if blocking:
+			while not self.txqueue.empty():
+				sleep(0.01)
+
+
+

test_images/compress_test_images.py

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+#!/usr/bin/env python
+#
+# Quick script to resize and SSDV-compress a selection of test images.
+# Original resolution: 1488x1120
+#	800x600
+#	640x480
+#	320x240
+#
+#	Requires:
+#		Imagemagick
+#		ssdv (https://github.com/fsphil/ssdv)
+
+import os, glob
+
+# images should be named 1.jpg, 2.jpg, etc.
+image_numbers = xrange(1,14)
+new_sizes = ["800x608","640x480","320x240"]
+callsign = "VK5QI"
+
+# Resize images.
+for x in image_numbers:
+	# make a copy of the raw image.
+	os.system("cp %d.jpg %d_raw.jpg" % (x,x))
+	# Produce resized images.
+
+	for size in new_sizes:
+		os.system("convert %d.jpg -resize %s\! %d_%s.jpg" % (x,size,x,size))
+
+# Compress with SSDV.
+new_sizes.append("raw")
+
+for x in image_numbers:
+	for size in new_sizes:
+		os.system("ssdv -e -c %s -i %d %d_%s.jpg %d_%s.ssdv" % (callsign,x,x,size,x,size))

tx_test_images.py

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+#
+#	Test Transmitter Script
+#	Transmit a set of images from the test_images directory
+#
+#	Mark Jessop <vk5qi@rfhead.net>
+#
+
+import PacketTX,  sys, os
+
+# Set to whatever resolution you want to test.
+file_path = "./test_images/%d_800x608.ssdv" # _raw, _800x608, _640x480, _320x240
+image_numbers = xrange(1,14)
+
+def transmit_file(filename, tx_object):
+	file_size = os.path.getsize(filename)
+
+	if file_size % 256 > 0:
+		print("File size not a multiple of 256 bytes!")
+		return
+
+	print("Transmitting %d Packets." % (file_size/256))
+
+	f = open(filename,'rb')
+
+	for x in range(file_size/256):
+		data = f.read(256)
+		tx_object.tx_packet(data)
+
+	f.close()
+	print("Waiting for tx queue to empty...")
+	tx_object.wait()
+
+
+tx = PacketTX.PacketTX()
+tx.start_tx()
+
+for img in image_numbers:
+	filename = file_path % img
+	print("\nTXing: %s" % filename)
+	transmit_file(filename,tx)
+
+tx.close()