Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I have used the code above but added two other function calls as well to convert the image so that it will work with the Tesseract.</p> <p>Firstly I used an image resize script to convert to 640 x 640 which seems to be more manageable for the Tesseract. </p> <pre><code>-(UIImage *)resizeImage:(UIImage *)image { CGImageRef imageRef = [image CGImage]; CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGColorSpaceCreateDeviceRGB(); if (alphaInfo == kCGImageAlphaNone) alphaInfo = kCGImageAlphaNoneSkipLast; int width, height; width = 640;//[image size].width; height = 640;//[image size].height; CGContextRef bitmap; if (image.imageOrientation == UIImageOrientationUp | image.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, alphaInfo); } else { bitmap = CGBitmapContextCreate(NULL, height, width, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, alphaInfo); } if (image.imageOrientation == UIImageOrientationLeft) { NSLog(@"image orientation left"); CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -height); } else if (image.imageOrientation == UIImageOrientationRight) { NSLog(@"image orientation right"); CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -width, 0); } else if (image.imageOrientation == UIImageOrientationUp) { NSLog(@"image orientation up"); } else if (image.imageOrientation == UIImageOrientationDown) { NSLog(@"image orientation down"); CGContextTranslateCTM (bitmap, width,height); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage *result = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return result; } </code></pre> <p>So that the radians work ensure you declare it above the <code>@implementation</code></p> <pre><code>static inline double radians (double degrees) {return degrees * M_PI/180;} </code></pre> <p>Then I convert to grayscale.</p> <p>I found this article <a href="https://stackoverflow.com/questions/1298867/convert-image-to-grayscale">Convert image to grayscale</a> on converting to grayscale.</p> <p>I have used the code from here successfully and can now read different colour text and different colour backgrounds</p> <p>I have modified the code slightly to work as a function within a class rather than as its own class which the other person did</p> <pre><code>- (UIImage *) toGrayscale:(UIImage*)img { const int RED = 1; const int GREEN = 2; const int BLUE = 3; // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0, 0, img.size.width * img.scale, img.size.height * img.scale); int width = imageRect.size.width; int height = imageRect.size.height; // the pixels will be painted to this array uint32_t *pixels = (uint32_t *) malloc(width * height * sizeof(uint32_t)); // clear the pixels so any transparency is preserved memset(pixels, 0, width * height * sizeof(uint32_t)); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // create a context with RGBA pixels CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, width * sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast); // paint the bitmap to our context which will fill in the pixels array CGContextDrawImage(context, CGRectMake(0, 0, width, height), [img CGImage]); for(int y = 0; y &lt; height; y++) { for(int x = 0; x &lt; width; x++) { uint8_t *rgbaPixel = (uint8_t *) &amp;pixels[y * width + x]; // convert to grayscale using recommended method: http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale uint32_t gray = 0.3 * rgbaPixel[RED] + 0.59 * rgbaPixel[GREEN] + 0.11 * rgbaPixel[BLUE]; // set the pixels to gray rgbaPixel[RED] = gray; rgbaPixel[GREEN] = gray; rgbaPixel[BLUE] = gray; } } // create a new CGImageRef from our context with the modified pixels CGImageRef image = CGBitmapContextCreateImage(context); // we're done with the context, color space, and pixels CGContextRelease(context); CGColorSpaceRelease(colorSpace); free(pixels); // make a new UIImage to return UIImage *resultUIImage = [UIImage imageWithCGImage:image scale:img.scale orientation:UIImageOrientationUp]; // we're done with image now too CGImageRelease(image); return resultUIImage; } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POiOS Tesseract OCR Image Preperation
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USAdam Richardson
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COi have been trying this, and my images are converted, however, the UIImage still crashes on my iPhone. Any suggestions? Can you provide your source code?
      singulars
      1. PO
      1. USTha Leang
    2. COAre you returning an image from the camera or are you loading it from another source? Also the code I have provided above assumes that you are using ARC, if you are not then you will need to release the image and other objects at the appropriate time otherwise you will get crashes due to the memory load.
      singulars
      1. PO
      1. USAdam Richardson
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload