Can someone tell me how can I view an RGBA image? I just want a tool that I can display an RGBA image with!
I have written a code, which outputs only RGBA format. I just want to verify if my code worked, and just want to find a simple tool to view this image.
I wasn't able to come across a software to be able to display a RGBA image.
Thanks in advance.
RGBA files only contain raw channel data. The binary data will not have enough information to display an image (ie. width,height,depth, &tc).
If you know the image dimensions of each .rgba file, you should be able to work with the data. Here's an example of viewing raw date in javascript.
var fr = new FileReader(),
myWidth = 200,
myHeight = 200;
fr.onload = function(frEvent) {
var canvasElement = document.getElementById("myCanvas"),
ctx = canvasElement.getContext("2d"),
blob = ctx.createImageData(myWidth,myHeight),
index = 0;
while(index < frEvent.target.result.length)
blob.data[index] = frEvent.target.result.charCodeAt(index++);
ctx.putImageData(blob,0,0);
}
Imagemagick will be able to display raw RGBA data. Assuming that each color sample is 8 bits.
display -size 200x200 -depth 8 mySimpleData.rgba
Related
Here I have a image:
Then I have generated threshold image using the code below.
img = cv2.imread('Image_Original.jpg')
hsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
lower_gr = np.array([40,0,0])
upper_gr = np.array([90,255,255])
mask = cv2.inRange(hsv,lower_gr,upper_gr)
mask=~mask
res = cv2.bitwise_and(img,img,mask = ~mask)
cv2.imshow('Masked',mask)
cv2.imshow('Result',res)
Then the following images (masked):
and (result):
Now what I want is to remove the black pixels(FROM THE ORiGINAL IMAGE ONLY) by making them zero and I want to extract only patches of size 32x32px or more.
Use cv2.findContours() to find the boundaries of the white patches in your mask image.
Each boundary is returned as a list of 2D points.
Use cv2.boundingRect() to get the width/height of each patch and filter accordingly.
You could also use cv2.minAreaRect(), or cv2.contourArea() to filter based on actual area of the patch.
https://docs.opencv.org/2.4/modules/imgproc/doc/structural_analysis_and_shape_descriptors.htm
Once you have determined which patches should be discarded, overwrite them with black on the colour image using cv2.fillPoly().
I'm trying to implement the Gaussian blur filter on Graphics object, but I can't find function for get pixel information or transform Graphics object to byte array (with RGB data).
That isn't supported since hardware accelerated surfaces might not provide that information.
However, you can do something else. Just paint the current form onto a mutable image and then just get the RGB of the mutable image which you can then use to create a new Image from an RGB e.g. something close to this:
Display d = Display.getInstance();
Image img = Image.createImage(d.getDisplayWidth(), d.getDisplayHeight());
Graphics g = img.getGraphics();
d.getCurrent().paintBackgrounds(g);
d.getCurrent().paintComponent(g, false);
int[] bufferArray = img.getRGB();
// blur...
Image blurredImage = Image.createImage(bufferArray, img.getWidth(), img.getHeight());
So I have the following script to resize an incoming jpg and save it to the server in a new size. The created jpg file has terrible quality, even when I am making the quality 90 on the imagejpeg. I am wondering if I am messing it up earlier in my efforts.
// Get new sizes
list($width, $height) = getimagesize($filename);
$percentW=298/$width;
$newwidth = $width * $percentW;
$newheight = $height * $percentW;
// Creating a blank canvas to put the new file. Is this an extra step?
$thumb = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefromjpeg($filename);
// Now I create the resized photo with the needed width and height on the blank canvas with the source file resized
imagecopyresampled($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
// Output to server, define 90% quality. My guess is the quality is destroyed before now.
imagejpeg($thumb,"../../uploads/buckets/" . $_POST["bucket"] . "/" .$fileNameBucket,90);
imagedestroy($thumb);
Am I messing up the quality before I even output the file to the server? Should I use resample instead of resize? I am stuck with using the GD library so ImageMagick is not an option. Thanks.
I'm trying to capture images within node.js from a webcam connected to a Raspberry Pi. Capturing works fine, but now when I want to transmit the images I have some serious problems with framerate and lags.
Now my first idea was to convert the RGB images to 8bit grayscale, that should increase the performance by factor 3 (i hope..).
I'm using node.js and opencv-node for this. Here you can see some code snippet for the moment:
var startT = new Date().getTime();
var capture = new cv.VideoCapture();
var frame = new cv.Mat;
var grey = new cv.Mat;
var imgPath = __dirname + "/ramdisk/";
var frame_number = 0;
capture.open(0);
if (!capture.isOpened())
{
console.log("aCapLive could not open capture!");
return;
}
function ImgCap()
{
var elapsed = (new Date().getTime() - startT) / 1000;
capture.read(frame);
cv.imwrite(imgPath+".bmp", frame);
id = setImmediate(ImgCap);
}
ImgCap();
I tried to use something like
cv.cvtColor(frame, grey, "CV_BGR2GRAY");
after reading the image but i only get some TypeError saying that argument 2 has to be an integer... I dont know what to do at the moment. I referred to http://docs.opencv.org/doc/tutorials/introduction/load_save_image/load_save_image.html#explanation for converting a rgb to a grayscale image.
Beside I'm still not sure if this just gives mit a 24bit grayscale image instead of 8bit..?!
Thanks for any help in advance! :)
use CV_BGR2GRAY instead of "CV_BGR2GRAY".
the former is an integral constant, the latter a char*
and, no fear, that will be 8bit grayscale.
In the Haxe programming language, is there any cross-language way to save an array of pixel data to a file (e. g., in BMP or PNG format)?
class SavePixelsToFile {
static function main(){
//how can I save this array of pixel data to a file? It is a simple 2D array of RGB arrays, with the red, green, and blue components in the respective order.
var arr = [
[[0, 0, 0],[255, 255, 255]],
[[255, 255, 255],[0, 0, 0]]
];
}
}
The format library will do what you want. http://code.google.com/p/hxformat/
Install this library: haxelib install format
Link it in your hxml file using: -lib format
To write image data to a file, do the following:
function writePixels24(file:String, pixels:haxe.io.Bytes, width:Int, height:Int) {
var handle = sys.io.File.write(file, true);
new format.png.Writer(handle)
.write(format.png.Tools.build24(width, height, pixels));
handle.close();
}
var bo = new haxe.io.BytesOutput();
for (pixel in pixels)
for (channel in pixel)
bo.writeByte(channel);
var bytes = bo.getBytes();
writePixels24("Somefile.png", bytes);
This will work for targets that have the sys.* package (Not flash). you can still generate the png without the sys.* package, but will need an alternate method of saving the file.
An easy to write format is PPM. The netpbm tools can easily manipulate those and also convert to many formats including PBM and PNG.