image-compression

问题 I=imread('cameraman.tif'); figure(1),imshow(I) I1=im2double(I); [U,S,V]=svd(I1); figure(2),imshow(I1) for j=1:90 I2=U(:,1:j)*S(1:j,1:j)*V(:,1:j)'; end figure(3),imshow(I2) I3=U*S*V'; figure(4),imshow(I3) this is the code i have written for SVD decomposition ,i got correct output.But the size of compressed image is greater than original image,so how to calculate whether after svd image is compressed or not,that means i got size of the image on disk after applying svd iterations is greater than

问题 This is not a straightforward problem, please read through! I want to manipulate a JPEG file and save it again as JPEG. The problem is that even without manipulation there's significant (visible) quality loss. Question : what option or API am I missing to be able to re-compress JPEG without quality loss (I know it's not exactly possible, but I think what I describe below is not an acceptable level of artifacts, especially with quality=100). Control I load it as a Bitmap from the file:

问题 This is not a straightforward problem, please read through! I want to manipulate a JPEG file and save it again as JPEG. The problem is that even without manipulation there's significant (visible) quality loss. Question : what option or API am I missing to be able to re-compress JPEG without quality loss (I know it's not exactly possible, but I think what I describe below is not an acceptable level of artifacts, especially with quality=100). Control I load it as a Bitmap from the file:

问题 Is there a way, in Java, to compute what the size of a compressed image will be w/o saving the image? (This will be used to determine the quality necessary to compress an image to a specific size.) Something like this, but in Java instead of C#, and where the Stream can be a dead end. 回答1: Here's a simple implementation. public class LengthCounterOutputStream extends OutputStream{ private int byteCounter = 0; @Override public void write(int b){ byteCounter++; } @Override public void write(

问题 I'm building a website which will have a lot of user uploaded images. I would like to resize and compress (preferably change their format to .jpg) these images client side, before uploading them to a server. How would one go about doing this? I have found a few solutions, but none that really work on uploaded files. The latest I've tried is the Hermite-resize script. Should be as simple as: // Get images from input field var uploadedImages = event.currentTarget.files; var HERMITE = new

问题 I'm using following code from here. I want to compress image. BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; Bitmap bmp = BitmapFactory.decodeFile(filePath, options); int actualHeight = options.outHeight; int actualWidth = options.outWidth; After choose image from Camera, Gallery and Photos, i'm getting different type of paths in different devices based on OS type and device model. like: 1) /storage/emulated/0/Android/data/... 2) /raw//storage

问题 Here is the function that compress image file. function compress_image($source_url, $destination_url, $quality) { $info = getimagesize($source_url); if ($info['mime'] == 'image/jpeg'){ $image = imagecreatefromjpeg($source_url); }elseif ($info['mime'] == 'image/gif') { $image = imagecreatefromgif($source_url); }elseif ($info['mime'] == 'image/png') { $image = imagecreatefrompng($source_url); }imagejpeg($image, $destination_url, $quality); return $destination_url; } $filename = compress_image($

问题 I am trying to upload picture using camera. I am uploading it to server Clicking image and showing it in imageview ( DONE) Compressing the image size to upload (Not Working) Uploading image to S3 (with uncompressed image) (DONE) This is my onActivityResult() case CAMERA_REQUEST: { Uri selectedImage = data.getData(); String[] filePathColumn = { MediaStore.Images.Media.DATA }; Cursor cursor = getContentResolver().query(selectedImage, filePathColumn, null, null, null); cursor.moveToFirst(); int

问题 I'm trying to create a code to decompress an RLE Byte-Oriented image from a PostScript File I've already tried solutions found around the web and also tried to build my own ; but none of them produced the result i need. After decompressing the rle image, i should have an RAW image i can open on photoshop (informing width, height and number of channels). However when i try to open the extracted image it doesn't work ; only a black output is show. My inputs are an Binary ASCII Encoded file

问题 I have few tif images which open on imread or cvLoadImage gives null data in windows whereas the same file is processed conveniently on ubuntu installation. Running imagemagik identify returns $identify 60018969.tif 60018969.tif[0] TIFF 1696x2192 1696x2192+0+0 8-bit Grayscale DirectClass 516KB 0.000u 0:00.040 60018969.tif[1] TIFF 1696x2192 1696x2192+0+0 8-bit Grayscale DirectClass 516KB 0.000u 0:00.030 60018969.tif[2] TIFF 1696x2376 1696x2376+0+0 8-bit Grayscale DirectClass 516KB 0.000u 0:00