What is the class_colors?

[Ikhwansong]

Hi ! Thanks for your sharing the code.

According to the source code, the class_colors was not used in anywhere.

Why did you write the code like this?

[ChunML]

Hi, that's for folks that want a different color for each class, otherwise, only the green color (default implementation) will be used.

[Ikhwansong]

This is code for the random colorizing.

class ImageVisualizer_cv2(object):

def __init__(self, idx_to_name, class_colors = None, save_dir = None):
    self.idx_to_name = idx_to_name
    self.color_matrix = self._colorizing()
    self.color_matrix = np.random.shuffle(self.color_matrix)

    if save_dir is None:
        self.save_dir = './'
    else:
        self.save_dir = save_dir

    os.makedirs(self.save_dir, exist_ok=True)

def _colorizing(self,):
    factor = math.floor(math.pow(len(self.idx_to_name), 1/3))
    color_divider = 255/factor
    color_matrix = np.zeros(((factor+1)*(factor+1)*(factor+1),3))
    index = 0
    for x in range(factor+1):
        for y in range(factor+1) :
            for z in range(factor+1) :
                color_matrix[index,:] = np.array([x*color_divider, y*color_divider, z*color_divider])
                index = index + 1 
    return color_matrix[1:-1]

def save_image(self, img_path, boxes, labels, name):
    img  = cv2.imread(img_path)
    save_path = os.path.join(self.save_dir, name)

    for i, box in enumerate(boxes):
        idx = labels[i] -1
        cls_name = self.idx_to_name[idx]
        top_left = (box[0], box[1])
        bot_right = (box[2], box[3])
        cv2.rectangle(img,top_left, bot_right, self.color_matrix[idx], 1 )
        cv2.putText(img, cls_name, top_left,1, (255,255,255), 1)

    cv2.imwrite(save_path, img)

For example, If the len of class is the number of 27, It generate 444 number of cases and perform random matching the class name with one color pair except two colors (white and black). It means the dog only have the one color forever. (Ex. dog = red)