tesseract的vb.net代码示例

以下是使用 tesseract 进行 OCR 的 VB.NET 代码示例：

Imports System
Imports System.IO
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.Diagnostics
Imports System.Runtime.InteropServices

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim inputFile As String = "test.png"
        Dim outputFile As String = "output.txt"
        Dim tesseractPath As String = "C:\Program Files (x86)\Tesseract-OCR\tesseract.exe"

        ' Convert the input image to grayscale
        Dim bmp As New Bitmap(inputFile)
        Dim grayBmp As New Bitmap(bmp.Width, bmp.Height, Imaging.PixelFormat.Format8bppIndexed)
        Using g As Graphics = Graphics.FromImage(grayBmp)
            Dim colorMatrix As New ColorMatrix(New Single()() _
                {New Single() {0.3F, 0.3F, 0.3F, 0, 0},
                 New Single() {0.59F, 0.59F, 0.59F, 0, 0},
                 New Single() {0.11F, 0.11F, 0.11F, 0, 0},
                 New Single() {0, 0, 0, 1, 0},
                 New Single() {0, 0, 0, 0, 1}})
            Dim ia As New ImageAttributes()
            ia.SetColorMatrix(colorMatrix)
            g.DrawImage(bmp, New Rectangle(0, 0, bmp.Width, bmp.Height), _
                        0, 0, bmp.Width, bmp.Height, GraphicsUnit.Pixel, ia)
        End Using

        ' Save the grayscale image to a file
        grayBmp.Save("temp.tif", Imaging.ImageFormat.Tiff)

        ' Run tesseract on the grayscale image
        Dim processInfo As New ProcessStartInfo()
        processInfo.FileName = tesseractPath
        processInfo.Arguments = "temp.tif " & outputFile & " -l eng"
        processInfo.CreateNoWindow = True
        processInfo.UseShellExecute = False
        processInfo.RedirectStandardOutput = True
        processInfo.RedirectStandardError = True

        Dim process As Process = Process.Start(processInfo)
        process.WaitForExit()

        ' Load the output text file and display the result
        Dim outputText As String = File.ReadAllText(outputFile)
        MessageBox.Show(outputText)

        ' Delete the temporary files
        File.Delete("temp.tif")
        File.Delete(outputFile)
    End Sub

End Class

请注意，您需要在计算机上安装 tesseract OCR 引擎，并相应地更新 `tesseractPath` 变量。此外，您也可以根据需要更改语言设置。