[英]opencv cv2.imwrite error after image transform
import cv2
import numpy as np
def prepare_data_test(test_path):
input_names = []
for dirname in test_path:
for _, _, fnames in sorted(os.walk(dirname)):
for fname in fnames:
if is_image_file(fname):
input_names.append(os.path.join(dirname, fname))
return input_names
def is_image_file(filename):
return any(filename.endswith(extension) for extension in IMG_EXTENSIONS)
IMG_EXTENSIONS = [
'.jpg', '.JPG', '.jpeg', '.JPEG',
'.png', '.PNG', '.ppm', '.PPM', '.bmp', '.BMP',
]
test_path = ["./figures/"] # ["./test_images/real/"]
subtask = "dataset" # if you want to save different testset separately
val_names = prepare_data_test(test_path)
num=1
for val_path in val_names:
im = cv2.imread(val_path)#3채
img = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY) # no channel
dx = cv2.Sobel(img, cv2.CV_32F, 1, 0) # float 형태의 미분값을 저장
dy = cv2.Sobel(img, cv2.CV_32F, 0, 1)
mag = cv2.magnitude(dx, dy) # gradient magnitude , no channel
mag = np.clip(mag, 0, 255).astype(np.uint8) # 255보다 커질 수 있으므로 saturate 연산
#mag = np.expand_dims(mag, axis=2)
mag = cv2.cvtColor(mag, cv2.COLOR_GRAY2RGB) # convert mag to RGBA 채널: 3
mag = cv2.cvtColor(mag, cv2.COLOR_RGB2GRAY) #width, height 채널 없어짐
mag = np.expand_dims(mag, axis=2)
print(mag.shape)
#concat = np.concatenate([im,mag],-1)
concat = np.concatenate([im,mag], axis = 2)
outfile = 'output%s.jpg' % (num)
cv2.imwrite(outfile, concat)##### it saved im image error
num = num + 1
cv2.waitKey()
cv2.destroyAllWindows()
我制作了梯度幅度图像,然后我制作了连接图像作为输入图像和梯度图像,我想保存连接图像但是为什么 opencv 没有保存连接图像,它保存了输入图像我得到了错误 cv2.imwrite
如果要并排显示原始图像和梯度幅度(如附图所示), np.concatenate
应与axis=1
一起使用,而不是与axis=2
一起使用:
# Convert gradient magnitude to BGR so make shape compatible with im's shape.
mag_vis = cv2.cvtColor(mag, cv2.COLOR_GRAY2BGR)
concat = np.concatenate([im, mag_vis], axis=1)
照原样,您沿着通道维度连接,并最终得到一个 4 通道图像。
另一方面,如果这是有意的——如果你想将具有梯度幅度的 BGRA 图像保存为 alpha 通道——你可能会考虑将图像保存为.png
,而不是.jpg
。
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