For a website I run, users can upload pictures they've drawn to a gallery. We create a thumbnail and a small view of that image to display to other users (clicking the small view image shows the full sized image). With this in mind, I created a very simple resize script. In most cases this script works perfectly. However, I've come a...
Hey I'm doing some image processing, and am trying to keep track of points similar to those circled below, a very dark spot of a couple of pixels diameter, with all neighbouring pixels being bright. I'm sure there are algorithms and methods which are designed for this, but I just don't know what they are. I don't think edge detection wo...
Hi all, I'm looking for a way of converting an image so that all non-transparent pixels (those that have alpha != 1) into black and transparent pixels untouched (or converted to white). The closest I got was with the below imagemagick command: convert <img> -colorspace Gray <out> However this still gives me some gray colors instead o...
Task is following: how to create selected picture mosaic from large number of images. My first shot would be using evolutionary algorithm. Where genotype represents mapping of original images to positions in mosaic grid, and individual is evaluated according to similarity to original picture. Actually in basic approach each tile can be t...
It's easy to resize images so that they all have the same height while maintaining the aspect ratio, but how did they fit them all on a row such that every row has the same width? Did they crop some of the images or what? For those flagging this as "off-topic" -- I thought "algorithms for organizing images" was within the realm of p...
A JPEG image, if it is non-progrssive loads from top-to-bottom, and not from left-to-right or any other manner. Doesn't that imply that jpeg uses some row-wise compression technique? Does it (use a row-wise compression technique)? ...
Im developing an image analysis app and need to calculate the aspect ratio of a segmented particle. According to http://www.sympatec.com/Science/Characterisation/05_ParticleShape.html the AR is given by (FIG 1) Xfmin/Xfmax. Any suggestion of an algorithm to get this values (Xf)? ...
I'm processing a bunch of images with some framework, and all I'm given is a bunch of BufferedImage objects. Unfortunately, these images are really dim, and I'd like to brighten them up and adjust the contrast a little. Something like: BufferedImage image = something.getImage(); image = new Brighten(image).brighten(0.3); // for 30% ima...
Hi Do you know any algorithm to create HDR images, like photomatix or photoshop "merge hdr" function? ...
Does any one have an idea regarding what sort of algorithm might Google be using to find similar images ? ...
I'm trying to detect the first valley in a 1D histogram, to use as a threshold point. (Processing dark to light / left to right) Unfortunately some of the histograms have mini peaks, gaps and jagged edges. The algorithm I've written is getting stuck on these. I think I need to smooth away the rough edges as the peaks valleys I need are ...
Currently I'm using PhpThumb to save images: http://phpthumb.gxdlabs.com/ I already get a plugin to put watermarks: http://phpthumb.gxdlabs.com/forums/topic/watermark-plugin#post-115 Now, I would like to do a plugin to save images like that: The example can be just with php. Which is the best way to define a specific size and then p...
I am processing images to change their color from black to red, blue, green etc based on the requirement. I use SetPixel methods to change color of each pixel of the image from black to say red. It works mostly fine except the borders and some curves within the image. Let's say I've circled image filled with black color. Circled im...
I was wondering if anyone has any words of advice or could point me to any good resources regarding the creation of color lookup tables for image synthesis. In my application I have floating point values between -1.0 and 1.0 that need to be mapped onto RGB space. The problem is, I don't know beforehand what precision those floating point...
I am trying to do some manipulation (specifically, conversion to a different type of splitting into tiles) on a set of very large (a few GB) BMP image files. I'm not sure I understand the BMP file format, but is it necessary to load the entire file into memory? I was unable to find any API that didn't require loading the entire file at ...
Hi, I'm trying to find a real time image processing tool that can do image resizing, image/text overlaying and format converting. I found some related posts but they don't quite answer my question. Prioritized criteria for the tool: The processing time needs to be less than 100 ms. The size of output image needs to be small. It needs...
I want to display an image to my users which is larger than the screen area and will overscroll to let the users drag it around and zoom in. Do I need different images with different dpi for iPhone 4 users because of the higher resolution? Or can I just set the zoom level differently depending on device? ...
Im using CGBitmapContextCreate to read the data from a png file. I then resize the image with a couple of loops to fit the OpenGL ES image size criteria. I was wondering if there is a better way to this. Basically what I do now is have a nested loop like: for(i<newHeight){ for(j<newWidth){ copy image data } } For instanc...
I have a picture (jpg file, for example). I need to know "overall average" the color of the picture. I mean the prevailing color in this picture. I can not strictly furmulate my task. I will cite an example: (Image above: at the top - the original image, at the bottom - the "overall average" color which is associated with picture) ...
I have a number of images where I know the focal length, pixel count, dimensions and position (from GPS). They are all in a high oblique manner, taken on the ground with commercially available cameras. What would be the best method for calculating the euclidean distances between certain pixels within an image? If it is indeed possible...