Переделай код, чтобы при вводе порога, что входит в порог растягивалась, что не входит в порог не растягивалась. 
				private void brightness1Image() {
					if (image != null) {
					int minThreshold = 50;
					int maxThreshold = 50;

					// Create panels for min and max threshold values
					JPanel minThresholdPanel = new JPanel(new GridLayout(1, 2));
					JPanel maxThresholdPanel = new JPanel(new GridLayout(1, 2));

					// Create text fields for threshold values
					JTextField minThresholdField = new JTextField(Integer.toString(minThreshold));
					JTextField maxThresholdField = new JTextField(Integer.toString(maxThreshold));
					minThresholdPanel.add(new JLabel("Min threshold: "));
					maxThresholdPanel.add(new JLabel("Max threshold: "));
					minThresholdPanel.add(minThresholdField);
					maxThresholdPanel.add(maxThresholdField);

					// Create window for inputting threshold values
					int result = JOptionPane.showConfirmDialog(null, new Object[]{minThresholdPanel, maxThresholdPanel},
					"Enter Threshold Values", JOptionPane.OK_CANCEL_OPTION);

					if (result == JOptionPane.OK_OPTION) {
					// Update threshold values
					minThreshold = Integer.parseInt(minThresholdField.getText());
					maxThreshold = Integer.parseInt(maxThresholdField.getText());

					// Create new image for modified image
					BufferedImage modifiedImage = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);

					// Create color for black pixels
					Color black = Color.BLACK;

					for (int i = 0; i < image.getWidth(); i++) {
					for (int j = 0; j < image.getHeight(); j++) {
					// Get pixel and extract RGB values
					int pixel = image.getRGB(i, j);
					int red = (pixel >> 16) & 0xff;
					int green = (pixel >> 8) & 0xff;
					int blue = pixel & 0xff;

					// Calculate brightness of pixel
					int brightness = (int) (0.2126 * red + 0.7152 * green + 0.0722 * blue);

					Color c;
					// Check if brightness value exceeds min threshold
					if (brightness >= minThreshold) {
					c = new Color(255, 255, 255); // Set color to white
					} else {
					c = new Color(red, green, blue);
					}

					modifiedImage.setRGB(i, j, c.getRGB());
					}
					}

					if (modifiedImage != null) {
					setImageIcon(modifiedImage);
					saveImage(modifiedImage);

					// Create histogram for original image
					int[] originalHistogram = new int[256];
					for (int i = 0; i < image.getWidth(); i++) {
					for (int j = 0; j < image.getHeight(); j++) {
					// Get pixel and extract RGB values
					int pixel = image.getRGB(i, j);
					int red = (pixel >> 16) & 0xff;
					int green = (pixel >> 8) & 0xff;
					int blue = pixel & 0xff;

					// Calculate brightness of pixel
					int brightness = (int) (0.2126 * red + 0.7152 * green + 0.0722 * blue);

					originalHistogram[brightness]++;
					}
					}

					// Create histogram for modified image
					int[] modifiedHistogram = new int[256];
					for (int i = 0; i < modifiedImage.getWidth(); i++) {
					for (int j = 0; j < modifiedImage.getHeight(); j++) {
					// Get pixel and extract RGB values
					int pixel = modifiedImage.getRGB(i, j);
					int red = (pixel >> 16) & 0xff;
					int green = (pixel >> 8) & 0xff;
					int blue = pixel & 0xff;

					// Calculate brightness of pixel
					int brightness = (int) (0.2126 * red + 0.7152 * green + 0.0722 * blue);

					modifiedHistogram[brightness]++;
					}
					}

					// Create window for displaying histograms
					JFrame histogramFrame = new JFrame("Histograms");
					histogramFrame.setLayout(new GridLayout(2, 2, 10, 10));

					// Panel for original image histogram
					JPanel originalHistogramPanel = new JPanel() {
					@Override
					protected void paintComponent(Graphics g) {
					super.paintComponent(g);
					int max = Arrays.stream(originalHistogram).max().getAsInt();
					for (int i = 0; i < 256; i++) {
					int height = (int) (300.0 * originalHistogram[i] / max);
					g.fillRect(i, 300 - height, 1, height);
					}
					}
					};
					originalHistogramPanel.setBorder(BorderFactory.createLineBorder(Color.GRAY));
					originalHistogramPanel.setPreferredSize(new Dimension(256, 300));
					histogramFrame.add(new JLabel("Original Image"));
					histogramFrame.add(originalHistogramPanel);

					// Panel for modified image histogram
					JPanel modifiedHistogramPanel = new JPanel() {
					@Override
					protected void paintComponent(Graphics g) {
					super.paintComponent(g);
					int max = Arrays.stream(modifiedHistogram).max().getAsInt();
					for (int i = 0; i < 256; i++) {
					int height = (int) (300.0 * modifiedHistogram[i] / max);
					g.fillRect(i, 300 - height, 1, height);
					}
					}
					};
					modifiedHistogramPanel.setBorder(BorderFactory.createLineBorder(Color.GRAY));
					modifiedHistogramPanel.setPreferredSize(new Dimension(256, 300));
					histogramFrame.add(new JLabel("Modified Image"));
					histogramFrame.add(modifiedHistogramPanel);

					histogramFrame.pack();
					histogramFrame.setLocationRelativeTo(null);
					histogramFrame.setVisible(true);
					}
					}
					}
					}