For a small project, I need to compare one image with another – to determine if the images are approximately the same or not. The images are smallish, varying from 25 to 100px across. The images are meant to be of the same picture data but are sublty different, so a simple pixel equality check … Read more
I’m trying to do a perspective transformation of a set of points in order to achieve a deskewing effect: http://nuigroup.com/?ACT=28&fid=27&aid=1892_H6eNAaign4Mrnn30Au8d I’m using the image below for tests, and the green rectangle display the area of interest. I was wondering if it’s possible to achieve the effect I’m hoping for using a simple combination of cv::getPerspectiveTransform … Read more
I want to blur my image using the native Gaussian blur formula. I read the Wikipedia article, but I am not sure how to implement this. How do I use the formula to decide weights? I do not want to use any built in functions like what MATLAB has Answer Writing a naive gaussian blur … Read more
First of all I have this image and I want to make an application that can detect images like it and remove the circle (watermark) from it. int main(){ Mat im1,im2,im3,gray,gray2,result; im2=imread(” (2).jpg”); namedWindow(“x”,CV_WINDOW_FREERATIO); imshow(“x”,im2); //converting it to gray cvtColor(im2,gray,CV_BGR2GRAY); // creating a new image that will have the cropped ellipse Mat ElipseImg(im2.rows,im2.cols,CV_8UC1,Scalar(0,0,0)); //detecting the … Read more
I found JPG does not support transparency, the alpha value is always 255. I am wondering only png supports transparency? Answer png-32 supports different levels of transparency. Each pixel can have an opacity between 0 and 255, with 0 as completely transparent. png-24 supports setting one color as fully transparent. Everything else will be opaque. … Read more
Is there a way to convert an image to grayscale 16 bits per pixel format, rather than setting each of the r,g and b components to luminance. I currently have a bmp from file. Bitmap c = new Bitmap(“filename”); I want a Bitmap d, that is grayscale version of c. I do see a constructor … Read more
I have an image and I want to extract a region from it. I have coordinates of left upper corner and right lower corner of this region. In gray scale I do it like this: I = cv2.imread(“lena.png”) I = cv2.cvtColor(I, cv2.COLOR_RGB2GRAY) region = I[248:280,245:288] tools.show_1_image_pylab(region) I can’t figure it out how to do it … Read more
I have to create a PHP that will return an image stream of one transparent dot (PNG or GIF) Could you point me to an easy to use solution? Answer Transparent 1×1 PNG: header(‘Content-Type: image/png’); echo base64_decode(‘iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=’); Transparent 1×1 GIF: header(‘Content-Type: image/gif’); echo base64_decode(‘R0lGODlhAQABAJAAAP8AAAAAACH5BAUQAAAALAAAAAABAAEAAAICBAEAOw==’); AttributionSource : Link , Question Author : Community , Answer Author … Read more
I am new to opencv and trying to implement image matching between two images. For this purpose, I’m trying to understand the difference between feature descriptors, descriptor extractors and descriptor matchers. I came across a lot of terms and tried to read about them on the opencv documentation website but I just can’t seem to … Read more
I’ve got a JPEG image which was taken on an iphone. On my desktop PC (Windows Photo Viewer, Google Chrome, etc) the orientation is incorrect. I’m working on an ASP.NET MVC 3 web application where i need to upload photos (currently using plupload). I’ve got some server-side code to process images, including reading EXIF data. … Read more
