114 lines
3.1 KiB
Python
114 lines
3.1 KiB
Python
from PIL import Image
|
|
import numpy as np
|
|
from scipy.interpolate import interp1d
|
|
|
|
|
|
def resize_to_512_center(img, fill_color=(0, 0, 0, 0)):
|
|
|
|
# 计算缩放比例
|
|
original_width, original_height = img.size
|
|
ratio = min(512 / original_width, 512 / original_height)
|
|
|
|
# 等比缩放
|
|
new_size = (int(original_width * ratio), int(original_height * ratio))
|
|
resized_img = img.resize(new_size, Image.LANCZOS) # 高质量缩放算法
|
|
|
|
# 创建新画布
|
|
canvas = Image.new(img.mode, (512, 512), fill_color)
|
|
|
|
# 计算粘贴位置（居中）
|
|
paste_position = (
|
|
(512 - new_size[0]) // 2,
|
|
(512 - new_size[1]) // 2
|
|
)
|
|
|
|
# 合并图像（保持透明度）
|
|
canvas.paste(resized_img, paste_position)
|
|
|
|
|
|
return canvas
|
|
|
|
def apply_color_curves(img, curves):
|
|
"""
|
|
对图像应用颜色曲线调整
|
|
:param input_path: 输入图像路径
|
|
:param output_path: 输出图像路径
|
|
:param curves: 曲线配置字典，格式为：
|
|
{
|
|
'rgb': [(x1, y1), (x2, y2), ...], # 全局通道曲线
|
|
'r': [(x1, y1), (x2, y2), ...], # 红色通道曲线
|
|
'g': [(x1, y1), (x2, y2), ...], # 绿色通道曲线
|
|
'b': [(x1, y1), (x2, y2), ...] # 蓝色通道曲线
|
|
}
|
|
"""
|
|
if img.mode == 'P':
|
|
img = img.convert('RGB')
|
|
|
|
# 分离通道
|
|
channels = list(img.split())
|
|
|
|
# 处理每个颜色通道
|
|
for ch_idx, ch_name in enumerate(['r', 'g', 'b','a']):
|
|
# 合并全局和通道特定曲线
|
|
combined_points = []
|
|
if 'rgb' in curves and not ch_name=='a':
|
|
combined_points.extend(curves['rgb'])
|
|
if ch_name in curves:
|
|
combined_points.extend(curves[ch_name])
|
|
|
|
if not combined_points:
|
|
continue
|
|
|
|
# 生成LUT
|
|
points = sorted(combined_points, key=lambda x: x[0])
|
|
xs, ys = zip(*points)
|
|
|
|
# 自动选择插值方式
|
|
interpolation_kind = 'quadratic' if len(points) >= 3 else 'linear'
|
|
interpolator = interp1d(
|
|
xs, ys,
|
|
kind=interpolation_kind,
|
|
bounds_error=False,
|
|
fill_value=(ys[0], ys[-1])
|
|
)
|
|
|
|
# 创建查找表
|
|
x_range = np.arange(256)
|
|
y_new = interpolator(x_range)
|
|
y_new = np.clip(y_new, 0, 255).astype(np.uint8)
|
|
lut = y_new.tolist()
|
|
|
|
# 应用LUT
|
|
channels[ch_idx] = channels[ch_idx].point(lut)
|
|
|
|
# 合并通道并保存
|
|
merged_channels = channels
|
|
img_out = Image.merge(img.mode, merged_channels)
|
|
|
|
return img_out
|
|
|
|
|
|
# 使用示例
|
|
if __name__ == "__main__":
|
|
# S型曲线增强对比度
|
|
curves = {
|
|
'a': [
|
|
(60, 0),
|
|
(127, 127),
|
|
(170, 255)
|
|
]
|
|
}
|
|
|
|
# 红色通道增强中间调
|
|
# curves = {
|
|
# 'r': [
|
|
# (0, 0),
|
|
# (127, 160),
|
|
# (255, 255)
|
|
# ]
|
|
# }
|
|
img = Image.open('input.png')
|
|
# img = apply_color_curves(img, curves)
|
|
img = resize_to_512_center(img)
|
|
|
|
img.save('output.png') |