I am trying to use Haar cascade classifier for object detection.I have copied a code for haar cascade algorithm but its not working.It's giving error as
unknown url type: '//drive.google.com/drive/folders/11XfAPOgFv7qJbdUdPpHKy8pt6aItGvyg'
even though this link is working.
import urllib.request, urllib.error, urllib.parse
import cv2
import os
def store_raw_images():
neg_images_link = '//drive.google.com/drive/folders/11XfAPOgFv7qJbdUdPpHKy8pt6aItGvyg'
neg_image_urls = urllib.request.urlopen(neg_images_link).read().decode()
pic_num = 1
if not os.path.exists('neg'):
os.makedirs('neg')
for i in neg_image_urls.split('\n'):
try:
print(i)
urllib.request.urlretrieve(i, "neg/"+str(pic_num)+".jpg")
img = cv2.imread("neg/"+str(pic_num)+".jpg",cv2.IMREAD_GRAYSCALE)
# should be larger than samples / pos pic (so we can place our image on it)
resized_image = cv2.resize(img, (100, 100))
cv2.imwrite("neg/"+str(pic_num)+".jpg",resized_image)
pic_num += 1
except Exception as e:
print(str(e))
store_raw_images()
I am expecting output as set of negative images for creating dataset module for object detection.
I think the missing "https:" at the start of the url is the causing the specific error.
Furthermore, you cannot just load a drive folder when it is not shared (you should use the drive link) and event then it is not optimal, you have to parse the html response and it may not even work.
I strongly suggest you to use a normal HTTP server or the Google Drive python API.
I want to convert a jpg image to tiff.
I tried to do it with opencv with python.
import cv2
image = cv2.imread("image.jpg")
retval, buf = cv2.imencode(".tiff", image)
cv2.imwrite("out.tiff")
And I have this:
Process finished with exit code 136 (interrupted by signal 8: SIGFPE)
I referred this link
But I couldn't make it work.
Any help would be appreciated.
For me this version worked without errors:
import cv2
image = cv2.imread("image.jpg")
cv2.imwrite("out.tiff", image)
Why do you need the imencode? Using that gives the same resulting file for me, just creates a temporary memory buffered, already TIFF-compressed version of the image:
retval, buf = cv2.imencode(".tiff", image)
with open('out2.tiff', 'wb') as fout:
fout.write(buf.tostring())
I am creating a face recognition system using Python and idle on these versions:Python 3.6.1 :: Anaconda custom (64-bit),Anaconda 4.4,idle
When I try to train the face recognizer I am getting an error like:
AttributeError: module 'cv2.face' has no attribute 'LBPHFaceRecognizer'
Here i have attached the code
import cv2
import os
import numpy as np
from PIL import Image
# Path for face image database
path = 'dataset'
recognizer = cv2.face.LBPHFaceRecognizer()
def getImagesWithID(path):
imagePaths=[os.path.join(path,f) for f in os.listdir(path)]
faceSamples=[]
Ids=[]
for imagePath in imagePaths:
faceImg=Image.open(imagePath).convert('L')
faceNp=np.array(faceImg,'unit8')
ID=int(os.path.split(imagePath)[-1].split('.')[1])
faces.append(faceNP)
IDs.append(ID)
cv2.imshow("training",faceNp)
cv2.waitKey(10)
return np.array(IDs), faces
Ids,faces=getImagesWithID(path)
recognizer.train(faces,Ids)
recognizer.save('recognizer/trainningData.yml')
cv2.destroyAllWindows()
That is such an old version of OpenCV that they didn't even have Python docs for it.
Now going off of their C++ documentation, I would say the Python equivalent was cv2.createLBPHFaceRecognizer(). It was not yet moved to face by then.
I would highly recommend you update to at least OpenCV 3.X or else you'll keep running into these issues.
I was using OpenCV to read the images from a folder. A lot of messages like this show up:
Corrupt JPEG data: premature end of data segment
Premature end of JPEG file
Premature end of JPEG file
Premature end of JPEG file
How to catch this exception and remove these image files?
Since you said you are reading 'images' (multiple images), you would be looping through files in the folder that you are reading them from.
In that case, if you check if the image is valid or not by using the following :
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
you can then proceed to deleting files which are corrupt/bad.
I've been struggling to find a solution too. Read tens of articles, most of which just state that openCV does not throw errors and only outputs the error on stderr.
Some suggest to use PIL, but that does not detect most of the image corruptions. Usually only premature end of file.
However the same errors that OpenCV warns about can be detected via imagemagick.
Install imagemagick (https://imagemagick.org/)
Make sure you have it in the path.
Put the following sub into your code and call it to verify a file from wherever you need to. It also outputs errors to stderr, however it raises an error (thanks to "-regard-warnings")
import subprocess
def checkFile(imageFile):
try:
subprocess.run(["identify", "-regard-warnings", imageFile]).check_returncode()
return true
except (subprocess.CalledProcessError) as e:
return false
If you don't want the check to spam your outputs, add stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL params to the run function call.
On windows if you have not installed the legacy commands use the new syntax:
subprocess.run(["magick", "identify", "-regard-warnings", imageFile]).check_returncode()
OpenCV says something like
Corrupt JPEG data: premature end of data segment
or
Corrupt JPEG data: bad Huffman code
or
Corrupt JPEG data: 22 extraneous bytes before marker 0xd9
when loading a corrupt jpeg image with imread().
Can I somehow catch that? Why would I get this information otherwise?
Do I have to check the binary file on my own?
OpenCV (version 2.4) does not overwrite the basic error handling for libjpeg, making them 'uncatchable'. Add the following method to modules/highgui/src/grfmt_jpeg.cpp, right below the definition of error_exit():
METHODDEF(void)
output_message( j_common_ptr cinfo )
{
char buffer[JMSG_LENGTH_MAX];
/* Create the message */
(*cinfo->err->format_message) (cinfo, buffer);
/* Default OpenCV error handling instead of print */
CV_Error(CV_StsError, buffer);
}
Now apply the method to the decoder error handler:
state->cinfo.err = jpeg_std_error(&state->jerr.pub);
state->jerr.pub.error_exit = error_exit;
state->jerr.pub.output_message = output_message; /* Add this line */
Apply the method to the encoder error handler as well:
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = error_exit;
jerr.pub.output_message = output_message; /* Add this line */
Recompile and install OpenCV as usual. From now on you should be able to catch libjpeg errors like any other OpenCV error. Example:
>>> cv2.imread("/var/opencv/bad_image.jpg")
OpenCV Error: Unspecified error (Corrupt JPEG data: 1137 extraneous bytes before marker 0xc4) in output_message, file /var/opencv/opencv-2.4.9/modules/highgui/src/grfmt_jpeg.cpp, line 180
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
cv2.error: /var/opencv/opencv-2.4.9/modules/highgui/src/grfmt_jpeg.cpp:180: error: (-2) Corrupt JPEG data: 1137 extraneous bytes before marker 0xc4 in function output_message
(I've submitted a pull request for the above but it got rejected because it would cause issues with people reading images without exception catching.)
Hope this helps anyone still struggling with this issue. Good luck.
It could be easier to fix the error in the file instead of trying to repair the loading function of OpenCV. If you are using Linux you can use ImageMagick to make reparation to a set of images (is usual to have it installed by default):
$ mogrify -set comment 'Image rewritten with ImageMagick' *.jpg
This command changes a property of the file leaving the image data untouched. However, the image is loaded and resaved, eliminating the extra information that causes the corruption error.
If you need more information about ImageMagick you can visit their website: http://www.imagemagick.org/script/index.php
You cannot catch it if you use imread(). However there is imdecode() function that is called by imread(). Maybe it gives you more feedback. For this you would have to load the image into memory on your own and then call the decoder.
It boils down to: You have to dig through the OpenCV sources to solve your problem.
i had to deal with this recently and found a solution over here
http://artax.karlin.mff.cuni.cz/~isa_j1am/other/opencv/
i just need to make 2 edits # $cv\modules\highgui\src\grfmt_jpeg.cpp.
--- opencv-1.0.0.orig/otherlibs/highgui/grfmt_jpeg.cpp 2006-10-16 13:02:49.000000000 +0200
+++ opencv-1.0.0/otherlibs/highgui/grfmt_jpeg.cpp 2007-08-11 09:10:28.000000000 +0200
## -181,7 +181,7 ##
m_height = cinfo->image_height;
m_iscolor = cinfo->num_components > 1;
- result = true;
+ result = (cinfo->err->num_warnings == 0);
}
}
## -405,8 +405,9 ##
icvCvt_CMYK2Gray_8u_C4C1R( buffer[0], 0, data, 0, cvSize(m_width,1) );
}
}
- result = true;
+
jpeg_finish_decompress( cinfo );
+ result = (cinfo->err->num_warnings == 0);
}
}
I am using opencv python package to read some image and also met this error message. This error can not be catch by Python. But if you want to find which image is corrupted without recompiling opencv as #Robbert suggested, you can try the following method.
First, you can pinpoint the directory where the corrupt images reside, which is fairly easy. Then you go to the directory, and use mogrify command line tool provided by ImageMagick to change the image meta info, as suggest by #goe.
mogrify -set comment "errors fixed in meta info" -format png *.jpg
The above command will convert the original jpg image to png format and also clean the original image to remove errors in meta info. When you run mogrify command, it will also output some message about which image is corrupted in the directory so that you can accurately find the corrupted image.
After that, you can do whatever you want with the original corrupted jpg image.
Any one stumbles upon this post and reads this answer.
I had to get hold of a corrupted image file.
These websites can help you corrupt your file
Corrupt a file - The file corrupter you were looking for!
CORRUPT A FILE ONLINE
Corrupt my File
First and the third website was not that much useful.
Second website is interesting as I could set the amount of file that I need to corrupt.
OpenCV version I used here is 3.4.0
I used normal cv2.imread(fileLocation)
fileLocation Location of corrupted image file
OpenCV didn't show any error message for any of the corrupted files used here
First and Third website only gave one file and both had None stored in them, when I tried to print them
Second website did let me decide the amount of file that was needed to be corrupted
Corruption% Opencv message on printing the image
4% None
10% None
25% None
50% None Corrupt JPEG data: 3 extraneous bytes before marker 0x4f
75% None Corrupt JPEG data: 153 extraneous bytes before marker 0xb2
100% Corrupt JPEG data: 330 extraneous bytes before marker 0xc6 None
I guess the only check we have to make here would be
if image is not None:
Do your code or else pop an error
You can redirect stderr to a file, then after imread, search for the string "Huffman" inside that file. After searching the file, empty it. It works for me and now I am able to discard corrupted images and just process good ones.
If you load your image with imdecode, you can check errno :
std::vector<char> datas();
//Load yout image in datas here
errno = 0;
cv::Mat mat = cv::imdecode(datas, -1);
if (errno != 0)
{
//Error
}
(tested on OpenCV 3.4.1)
I found that the issue is in libjpeg. If OpenCV uses it, it gets error
Corrupt JPEG data: 22 extraneous bytes before marker 0xd9
You can try my solution to solve it. It disables JPEG during compilation. After that OpenCV cannot read/write, but it works.
cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local -D BUILD_SHARED_LIBS=OFF -D BUILD_EXAMPLES=OFF -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF -D WITH_JPEG=OFF -D WITH_IPP=OFF ..
I found an easy solution without the need to recompile openCV.
You can use imagemagick to detect the same errors, however it returns an error as expected. See the description here: https://stackoverflow.com/a/66283167/2887398