例程讲解17-Pixy-Emulation->pixy_uart_emulation仿真Pixy uart协议

# 仿真Pixy uart协议
#
# 该脚本允许您的OpenMV Cam在uart模式下模拟Pixy（CMUcam5）。
# 请注意，您需要为您的应用程序设置下面的lab颜色阈值。
#
# P4 = TXD
# P5 = RXD
#
# P7 = Servo 1
# P8 = Servo 2

# Pixy Parameters ############################################################

color_code_mode = 1 # 0 == Disabled, 1 == Enabled, 2 == Color Codes Only, 3 == Mixed

max_blocks = 1000
max_blocks_per_signature = 1000
min_block_area = 20

uart_baudrate = 19200

# Pan Servo
s0_lower_limit = 1000 # Servo pulse width lower limit in microseconds.
s0_upper_limit = 2000 # Servo pulse width upper limit in microseconds.

# Tilt Servo
s1_lower_limit = 1000 # Servo pulse width lower limit in microseconds.
s1_upper_limit = 2000 # Servo pulse width upper limit in microseconds.

analog_out_enable = False # P6 -> Analog Out (0v - 3.3v).
analog_out_mode = 0 # 0 == x position of largest blob - 1 == y position of largest blob

# Parameter 0 - L Min.
# Parameter 1 - L Max.
# Parameter 2 - A Min.
# Parameter 3 - A Max.
# Parameter 4 - B Min.
# Parameter 5 - B Max.
# Parameter 6 - Is Color Code Threshold? (True/False).
# Parameter 7 - Enable Threshold? (True/False).
lab_color_thresholds = [(0, 100, 40, 127, -128, 127, True, True), # Generic Red Threshold
                        (0, 100, -128, -10, -128, 127, True, True), # Generic Green Threshold
                        (0, 0, 0, 0, 0, 0, False, False),
                        (0, 0, 0, 0, 0, 0, False, False),
                        (0, 0, 0, 0, 0, 0, False, False),
                        (0, 0, 0, 0, 0, 0, False, False),
                        (0, 0, 0, 0, 0, 0, False, False)]

fb_pixels_threshold = 500 # minimum number of pixels that must be in a blob
fb_merge_margin = 5 # how close pixel wise blobs can be before merging

##############################################################################

e_lab_color_thresholds = [] # enabled thresholds
e_lab_color_code = [] # enabled color code
e_lab_color_signatures = [] # original enabled threshold indexes
for i in range(len(lab_color_thresholds)):
    if lab_color_thresholds[i][7]:
        e_lab_color_thresholds.append(lab_color_thresholds[i][0:6])
        e_lab_color_code.append(lab_color_thresholds[i][6])
        e_lab_color_signatures.append(i + 1)

import image, math, pyb, sensor, struct, time

# Camera Setup

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False)
sensor.set_auto_whitebal(False)

# LED Setup

red_led = pyb.LED(1)
green_led = pyb.LED(2)
blue_led = pyb.LED(3)

red_led.off()
green_led.off()
blue_led.off()

# DAC Setup

dac = pyb.DAC("P6") if analog_out_enable else None

if dac:
    dac.write(0)

# Servo Setup

min_s0_limit = min(s0_lower_limit, s0_upper_limit)
max_s0_limit = max(s0_lower_limit, s0_upper_limit)
min_s1_limit = min(s1_lower_limit, s1_upper_limit)
max_s1_limit = max(s1_lower_limit, s1_upper_limit)

s0_pan = pyb.Servo(1) # P7
s1_tilt = pyb.Servo(2) # P8

s0_pan.pulse_width(int((max_s0_limit - min_s0_limit) // 2)) # center
s1_tilt.pulse_width(int((max_s1_limit - min_s1_limit) // 2)) # center

s0_pan_conversion_factor = (max_s0_limit - min_s0_limit) / 1000
s1_tilt_conversion_factor = (max_s1_limit - min_s1_limit) / 1000

def s0_pan_position(value):
    s0_pan.pulse_width(round(s0_lower_limit + (max(min(value, 1000), 0) * s0_pan_conversion_factor)))

def s1_tilt_position(value):
    s1_tilt.pulse_width(round(s1_lower_limit + (max(min(value, 1000), 0) * s1_tilt_conversion_factor)))

# Link Setup

uart = pyb.UART(3, uart_baudrate, timeout_char = 1000)

def write(data):
    uart.write(data)

def available():
    return uart.any()

def read_byte():
    return uart.readchar()

# Helper Stuff

def checksum(data):
    checksum = 0
    for i in range(0, len(data), 2):
        checksum += ((data[i+1] & 0xFF) << 8) | ((data[i+0] & 0xFF) << 0)
    return checksum & 0xFFFF

def get_normal_signature(code):
    for i in range(len(e_lab_color_signatures)):
        if code & (1 << i):
            return e_lab_color_signatures[i]
    return 0

def to_normal_object_block_format(blob):
    temp = struct.pack("<hhhhh", get_normal_signature(blob.code()), blob.cx(), blob.cy(), blob.w(), blob.h())
    return struct.pack("<hh10s", 0xAA55, checksum(temp), temp)

def get_color_code_signature(code):
    color_code_list = []
    for i in range(len(e_lab_color_signatures)):
        if code & (1 << i):
            color_code_list.append(e_lab_color_signatures[i])
    octal = 0
    color_code_list_len = len(color_code_list) - 1
    for i in range(color_code_list_len + 1):
        octal += color_code_list[i] << (3 * (color_code_list_len - i))
    return octal

def to_color_code_object_block_format(blob):
    angle = int((blob.rotation() * 180) // math.pi)
    temp = struct.pack("<hhhhhh", get_color_code_signature(blob.code()), blob.cx(), blob.cy(), blob.w(), blob.h(), angle)
    return struct.pack("<hh12s", 0xAA56, checksum(temp), temp)

def get_signature(blob, bits):
    return get_normal_signature(blob.code()) if (bits == 1) else get_color_code_signature(blob.code())

def to_object_block_format(blob, bits):
    return to_normal_object_block_format(blob) if (bits == 1) else to_color_code_object_block_format(blob)

# FSM Code

fsm_state = 0
last_byte = 0

FSM_STATE_NONE = 0
FSM_STATE_ZERO = 1
FSM_STATE_SERVO_CONTROL_0 = 2
FSM_STATE_SERVO_CONTROL_1 = 3
FSM_STATE_SERVO_CONTROL_2 = 4
FSM_STATE_SERVO_CONTROL_3 = 5
FSM_STATE_CAMERA_CONTROL = 6
FSM_STATE_LED_CONTROL_0 = 7
FSM_STATE_LED_CONTROL_1 = 8
FSM_STATE_LED_CONTROL_2 = 9

def parse_byte(byte):
    global fsm_state
    global last_byte

    if fsm_state == FSM_STATE_NONE:
        if byte == 0x00: fsm_state = FSM_STATE_ZERO
        else: fsm_state = FSM_STATE_NONE

    elif fsm_state == FSM_STATE_ZERO:
        if byte == 0xFF: fsm_state = FSM_STATE_SERVO_CONTROL_0
        elif byte == 0xFE: fsm_state = FSM_STATE_CAMERA_CONTROL
        elif byte == 0xFD: fsm_state = FSM_STATE_LED_CONTROL_0
        else: fsm_state = FSM_STATE_NONE

    elif fsm_state == FSM_STATE_SERVO_CONTROL_0:
        fsm_state = FSM_STATE_SERVO_CONTROL_1

    elif fsm_state == FSM_STATE_SERVO_CONTROL_1:
        fsm_state = FSM_STATE_SERVO_CONTROL_2
        s0_pan_position(((byte & 0xFF) << 8) | ((last_byte & 0xFF) << 0))

    elif fsm_state == FSM_STATE_SERVO_CONTROL_2:
        fsm_state = FSM_STATE_SERVO_CONTROL_3

    elif fsm_state == FSM_STATE_SERVO_CONTROL_3:
        fsm_state = FSM_STATE_NONE
        s1_tilt_position(((byte & 0xFF) << 8) | ((last_byte & 0xFF) << 0))

    elif fsm_state == FSM_STATE_CAMERA_CONTROL:
        fsm_state = FSM_STATE_NONE
        # Ignore...

    elif fsm_state == FSM_STATE_LED_CONTROL_0:
        fsm_state = FSM_STATE_LED_CONTROL_1
        if byte & 0x80: red_led.on()
        else: red_led.off()

    elif fsm_state == FSM_STATE_LED_CONTROL_1:
        fsm_state = FSM_STATE_LED_CONTROL_2
        if byte & 0x80: green_led.on()
        else: green_led.off()

    elif fsm_state == FSM_STATE_LED_CONTROL_2:
        fsm_state = FSM_STATE_NONE
        if byte & 0x80: blue_led.on()
        else: blue_led.off()

    last_byte = byte

# Main Loop

pri_color_code_mode = color_code_mode % 4

def bits_set(code):
    count = 0
    for i in range(7):
        count += 1 if (code & (1 << i)) else 0
    return count

def color_code(code):
    for i in range(len(e_lab_color_code)):
        if code & (1 << i):
            return e_lab_color_code[i]
    return False

def fb_merge_cb(blob0, blob1):
    if not pri_color_code_mode:
        return blob0.code() == blob1.code()
    else:
        return True if (blob0.code() == blob1.code()) else (color_code(blob0.code()) and color_code(blob1.code()))

def blob_filter(blob):
    if(pri_color_code_mode == 0):
        return True
    elif(pri_color_code_mode == 1): # color codes with two or more colors or regular
        return (bits_set(blob.code()) > 1) or (not color_code(blob.code()))
    elif(pri_color_code_mode == 2): # only color codes with two or more colors
        return (bits_set(blob.code()) > 1)
    elif(pri_color_code_mode == 3):
        return True

clock = time.clock()
while(True):
    clock.tick()
    img = sensor.snapshot()
    blobs = list(filter(blob_filter, img.find_blobs(e_lab_color_thresholds, area_threshold = min_block_area, pixels_threshold = fb_pixels_threshold, merge = True, margin = fb_merge_margin, merge_cb = fb_merge_cb)))

    # Transmit Blobs #

    if blobs and (max_blocks > 0) and (max_blocks_per_signature > 0): # new frame
        dat_buf = struct.pack("<h", 0xAA55)
        sig_map = {}
        first_b = False

        for blob in sorted(blobs, key = lambda x: x.area(), reverse = True)[0:max_blocks]:
            bits = bits_set(blob.code())
            sign = get_signature(blob, bits)

            if not sign in sig_map:
                sig_map[sign] = 1
            else:
                sig_map[sign] += 1

            if sig_map[sign] <= max_blocks_per_signature:
                dat_buf += to_object_block_format(blob, bits)
                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())

            if dac and not first_b:
                x_scale = 255 / (img.width()-1)
                y_scale = 255 / (img.height()-1)
                dac.write(round((blob.y() * y_scale) if analog_out_mode else (blob.x() * x_scale)))
                first_b = True

        dat_buf += struct.pack("<h", 0x0000)
        write(dat_buf) # write all data in one packet...

    else: # nothing found
        write(struct.pack("<h", 0x0000))

        if dac:
            dac.write(0)

    # Parse Commands #

    for i in range(available()):
        parse_byte(read_byte())

    num_blobs = min(len(blobs), max_blocks)
    print("%d blob(s) found - FPS %f" % (num_blobs, clock.fps()))

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