Extracting text from pixel array

Aspose.OCR allows you to provide an image for recognition as an array of pixels. This can be useful when working with unsupported image formats.

The image is provided as an ImageDescriptor structure which describes image width, height, a number of bytes per pixel, and pixel colors. Pixels are listed from left to right (by line), and each line is added to the array from top to bottom.

Recognizing color images

The pixels are provided as a flat byte array representing the amount of each color (red, green and blue) per pixel. The amount can range from 0 to 255, where 0 means no that color and 255 is the maximum amount of that color. Set the channels_size member of ImageDescriptor structure to 3.

Recognizing grayscale images

The pixels are provided as a flat byte array representing the degree of pixel saturation (one byte per pixel). The number can range from 0 to 255, where 0 means black and 255 means white. Set the channels_size member of ImageDescriptor structure to 1.

Recognition methods

To extract text from an image provided as a pixel array, use one of the following methods:

Method	Description
page_from_raw_bytes()	Read the array with image pixels with automatic text areas detection and skew angle correction.
page_settings_from_raw_bytes()	Fine-tune recognition settings and read the byte array with image pixels.
page_all_from_raw_bytes()	Read the array with image pixels without text areas detection.
page_abc_from_raw_bytes()	Read only predefined list of characters from the array with image pixels.
page_abc_all_from_raw_bytes()	Read only predefined list of characters from the array with image pixels without text areas detection.

unsigned char*** img_raw = <...>;
ImageDescriptor descriptor;
descriptor.image_from_raw_bytes = img_raw;
descriptor.height = 2000;
descriptor.width = 800;
descriptor.channels_size = 3;
const size_t descriptor_size = sizeof descriptor;
const size_t len = 4096;
wchar_t buffer[len] = { 0 };
RecognitionSettings settings;
size_t res_len = aspose::ocr::page_from_raw_bytes(descriptor, descriptor_size, buffer, len);
std::wcout << buffer;