ascii-cam.py (with open-cv)

ascii-cam.py

try:
    import cv2
except ImportError:
    from cv2 import cv2


import numpy as np


def toASCII(frame, cols=120, rows=35):
    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    height, width = frame.shape
    cell_width = width / cols
    cell_height = height / rows
    if cols > width or rows > height:
        raise ValueError('Too many cols or rows.')
    result = ''
    for i in range(rows):
        for j in range(cols):
            outer_left = int(i * cell_height)
            inner_left = min(int((i + 1) * cell_height), height)
            inner_right = int(j * cell_width)
            outer_right = min(int((j + 1) * cell_width), width)

            frame_ = frame[outer_left:inner_left, inner_right:outer_right]
            gray = np.mean(frame_)

            result += grayToChar(gray)
        result += '\n'
    return result


def grayToChar(gray):
    CHAR_LIST = ' .:-=+*#%@'
    num_chars = len(CHAR_LIST)
    return CHAR_LIST[min(int(gray * num_chars / 255), num_chars - 1)]


def main():
    vc = cv2.VideoCapture('/dev/video4')

    if vc.isOpened():
        rval, frame = vc.read()
    else:
        rval = False

    while rval:
        rval, frame = vc.read()
        print(toASCII(frame))

        key = cv2.waitKey(50)  # 50ms pause -> ~20fps
        # Press echap to end
        if key == 27:
            break


if __name__ == '__main__':
    main()