8da27a1ead
- Add default yrow=8 when no mode specified - Make --output optional, auto-generate to results/ folder - Add 4-char UUID and threshold to auto-generated filenames - Auto-append .jpg extension when no extension provided - Rotate row mode output 90° clockwise for proper orientation - Move debug mode outputs to results/ folder - Add uuid module for unique filename generation Example outputs: - results/video_a3f2_t0_01.jpg (auto-generated) - results/video_7c91_t0_05_changes.png (debug mode)
450 lines
15 KiB
Python
450 lines
15 KiB
Python
#!/usr/bin/env python3
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"""
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Strip Photography / Slit Photography Implementation
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A digital implementation of strip photography that captures a two-dimensional
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image as a sequence of one-dimensional images over time.
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"""
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import argparse
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import sys
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import cv2
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import numpy as np
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import matplotlib.pyplot as plt
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from pathlib import Path
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import uuid
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def calculate_line_difference(line1, line2):
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"""
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Calculate the difference between two lines (column or row).
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Args:
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line1, line2: numpy arrays representing lines from consecutive frames
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Returns:
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float: normalized difference value between 0 and 1
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"""
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# Convert to float for calculation
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diff = np.abs(line1.astype(np.float32) - line2.astype(np.float32))
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# Calculate mean difference across all channels
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mean_diff = np.mean(diff)
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# Normalize to 0-255 range
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return mean_diff / 255.0
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def generate_change_graph(changes, output_path, threshold=None):
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"""
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Generate a graph showing change values over time.
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Args:
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changes: List of change values
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output_path: Path for output graph image
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threshold: Optional threshold line to display
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"""
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plt.figure(figsize=(12, 6))
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plt.plot(changes, linewidth=1, alpha=0.7)
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plt.xlabel('Frame Number')
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plt.ylabel('Change Value (0-1)')
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plt.title('Line Change Detection Over Time')
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plt.grid(True, alpha=0.3)
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if threshold is not None:
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plt.axhline(y=threshold, color='r', linestyle='--',
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label=f'Threshold: {threshold:.3f}')
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plt.legend()
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# Add statistics
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mean_change = np.mean(changes)
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max_change = np.max(changes)
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std_change = np.std(changes)
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stats_text = f'Mean: {mean_change:.3f}\nMax: {max_change:.3f}\nStd: {std_change:.3f}'
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plt.text(0.02, 0.98, stats_text, transform=plt.gca().transAxes,
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verticalalignment='top', bbox=dict(boxstyle='round', facecolor='wheat', alpha=0.8))
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plt.tight_layout()
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plt.savefig(output_path, dpi=150, bbox_inches='tight')
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plt.close()
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print(f"Change graph saved to: {output_path}")
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def analyze_changes_only(video_path, x_column=None, y_row=None, debug_output=None):
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"""
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Analyze changes in video without generating strip image.
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Used for debug mode to generate change threshold graphs.
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Args:
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video_path: Path to input video file
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x_column: X-coordinate of column to analyze (if column mode)
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y_row: Y-coordinate of row to analyze (if row mode)
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debug_output: Base path for debug outputs
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Returns:
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List of change values
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"""
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cap = cv2.VideoCapture(str(video_path))
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if not cap.isOpened():
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raise ValueError(f"Could not open video file: {video_path}")
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# Get video properties
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total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
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frame_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
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frame_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
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if x_column is not None:
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if x_column >= frame_width:
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raise ValueError(f"Column {x_column} is outside video width ({frame_width})")
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print(f"Analyzing column {x_column} from {frame_width}x{frame_height} frames")
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else:
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if y_row >= frame_height:
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raise ValueError(f"Row {y_row} is outside video height ({frame_height})")
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print(f"Analyzing row {y_row} from {frame_width}x{frame_height} frames")
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print(f"Processing {total_frames} frames for change analysis...")
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changes = []
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previous_line = None
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frame_idx = 0
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while True:
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ret, frame = cap.read()
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if not ret:
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break
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# Extract current line (column or row)
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if x_column is not None:
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current_line = frame[:, x_column, :].copy()
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else:
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current_line = frame[y_row, :, :].copy()
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# Calculate change from previous frame
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if previous_line is not None:
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change = calculate_line_difference(current_line, previous_line)
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changes.append(change)
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previous_line = current_line
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frame_idx += 1
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if frame_idx % 100 == 0:
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print(f"Analyzed {frame_idx}/{total_frames} frames")
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cap.release()
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if debug_output:
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# Generate change graph (debug_output is now a Path object)
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graph_path = debug_output.parent / f"{debug_output.stem}_changes.png"
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generate_change_graph(changes, graph_path)
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# Generate statistics
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if changes:
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print(f"\nChange Analysis Statistics:")
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print(f"Total frames analyzed: {len(changes)}")
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print(f"Mean change: {np.mean(changes):.4f}")
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print(f"Max change: {np.max(changes):.4f}")
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print(f"Min change: {np.min(changes):.4f}")
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print(f"Std deviation: {np.std(changes):.4f}")
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# Suggest thresholds
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percentiles = [50, 75, 90, 95, 99]
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print(f"\nSuggested threshold values:")
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for p in percentiles:
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thresh = np.percentile(changes, p)
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frames_above = np.sum(np.array(changes) >= thresh)
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compression = (len(changes) - frames_above) / len(changes) * 100
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print(f" {p}th percentile: {thresh:.4f} (keeps {frames_above} frames, {compression:.1f}% compression)")
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return changes
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def extract_column_strip(video_path, x_column, output_path, change_threshold=0.005):
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"""
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Extract vertical strip at x_column from each frame of the video.
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Only include frames where the change exceeds the threshold.
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Args:
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video_path: Path to input video file
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x_column: X-coordinate of the column to extract
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output_path: Path for output image
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change_threshold: Minimum change threshold (0-1) to include frame
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"""
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cap = cv2.VideoCapture(str(video_path))
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if not cap.isOpened():
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raise ValueError(f"Could not open video file: {video_path}")
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# Get video properties
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total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
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frame_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
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frame_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
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if x_column >= frame_width:
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raise ValueError(f"Column {x_column} is outside video width ({frame_width})")
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print(f"Processing {total_frames} frames...")
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print(f"Extracting column {x_column} from {frame_width}x{frame_height} frames")
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print(f"Change threshold: {change_threshold}")
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# Collect significant columns
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significant_columns = []
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previous_column = None
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included_frames = 0
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skipped_frames = 0
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frame_idx = 0
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while True:
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ret, frame = cap.read()
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if not ret:
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break
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# Extract current column
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current_column = frame[:, x_column, :].copy()
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# Check if this is the first frame or if change is significant
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include_frame = False
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if previous_column is None:
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include_frame = True # Always include first frame
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else:
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change = calculate_line_difference(current_column, previous_column)
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if change >= change_threshold:
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include_frame = True
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if include_frame:
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significant_columns.append(current_column)
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previous_column = current_column
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included_frames += 1
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else:
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skipped_frames += 1
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frame_idx += 1
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if frame_idx % 100 == 0:
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print(f"Processed {frame_idx}/{total_frames} frames")
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cap.release()
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if not significant_columns:
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raise ValueError("No significant changes detected. Try lowering the threshold.")
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# Convert list to numpy array
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strip_image = np.stack(significant_columns, axis=1)
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print(f"Original frames: {total_frames}")
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print(f"Included frames: {included_frames}")
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print(f"Skipped frames: {skipped_frames}")
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print(f"Compression ratio: {skipped_frames/total_frames:.1%}")
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print(f"Output dimensions: {strip_image.shape}")
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print(f"Saving to: {output_path}")
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# Save the strip image
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cv2.imwrite(str(output_path), strip_image)
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def extract_row_strip(video_path, y_row, output_path, change_threshold=0.01):
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"""
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Extract horizontal strip at y_row from each frame of the video.
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Only include frames where the change exceeds the threshold.
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Args:
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video_path: Path to input video file
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y_row: Y-coordinate of the row to extract
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output_path: Path for output image
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change_threshold: Minimum change threshold (0-1) to include frame
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"""
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cap = cv2.VideoCapture(str(video_path))
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if not cap.isOpened():
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raise ValueError(f"Could not open video file: {video_path}")
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# Get video properties
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total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
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frame_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
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frame_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
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if y_row >= frame_height:
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raise ValueError(f"Row {y_row} is outside video height ({frame_height})")
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print(f"Processing {total_frames} frames...")
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print(f"Extracting row {y_row} from {frame_width}x{frame_height} frames")
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print(f"Change threshold: {change_threshold}")
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# Collect significant rows
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significant_rows = []
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previous_row = None
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included_frames = 0
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skipped_frames = 0
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frame_idx = 0
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while True:
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ret, frame = cap.read()
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if not ret:
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break
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# Extract current row
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current_row = frame[y_row, :, :].copy()
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# Check if this is the first frame or if change is significant
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include_frame = False
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if previous_row is None:
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include_frame = True # Always include first frame
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else:
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change = calculate_line_difference(current_row, previous_row)
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if change >= change_threshold:
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include_frame = True
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if include_frame:
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significant_rows.append(current_row)
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previous_row = current_row
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included_frames += 1
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else:
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skipped_frames += 1
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frame_idx += 1
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if frame_idx % 100 == 0:
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print(f"Processed {frame_idx}/{total_frames} frames")
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cap.release()
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if not significant_rows:
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raise ValueError("No significant changes detected. Try lowering the threshold.")
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# Convert list to numpy array
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strip_image = np.stack(significant_rows, axis=0)
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# Rotate clockwise 90 degrees for row mode
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strip_image = cv2.rotate(strip_image, cv2.ROTATE_90_CLOCKWISE)
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print(f"Original frames: {total_frames}")
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print(f"Included frames: {included_frames}")
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print(f"Skipped frames: {skipped_frames}")
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print(f"Compression ratio: {skipped_frames/total_frames:.1%}")
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print(f"Output dimensions: {strip_image.shape} (rotated 90° CW)")
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print(f"Saving to: {output_path}")
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# Save the strip image
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cv2.imwrite(str(output_path), strip_image)
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def main():
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"""Main entry point for the strip photography tool."""
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parser = argparse.ArgumentParser(
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description="Extract strip photography effects from video files"
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)
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parser.add_argument(
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"video_file",
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help="Input video file path"
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)
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parser.add_argument(
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"--xcolumn",
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type=int,
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help="Extract vertical line at x-coordinate (column mode)"
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)
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parser.add_argument(
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"--yrow",
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type=int,
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help="Extract horizontal line at y-coordinate (row mode, default: 8)"
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)
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parser.add_argument(
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"--output",
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help="Output image file path (default: results/<input_name>.jpg)"
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)
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parser.add_argument(
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"--threshold",
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type=float,
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default=0.01,
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help="Change threshold (0-1) for including frames (default: 0.01)"
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)
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parser.add_argument(
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"--debug",
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action="store_true",
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help="Debug mode: analyze changes and generate threshold graph without creating strip image"
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)
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args = parser.parse_args()
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# Validate input file
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video_path = Path(args.video_file)
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if not video_path.exists():
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print(f"Error: Video file not found: {video_path}")
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sys.exit(1)
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# Validate mode selection
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if args.xcolumn is not None and args.yrow is not None:
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print("Error: Cannot specify both --xcolumn and --yrow. Choose one mode.")
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sys.exit(1)
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# Default to yrow=8 if neither mode specified
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if args.xcolumn is None and args.yrow is None:
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args.yrow = 8
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print(f"Using default: --yrow={args.yrow}")
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# Validate coordinates
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if args.xcolumn is not None and args.xcolumn < 0:
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print("Error: --xcolumn must be non-negative")
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sys.exit(1)
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if args.yrow is not None and args.yrow < 0:
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print("Error: --yrow must be non-negative")
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sys.exit(1)
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# Validate threshold
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if not (0 <= args.threshold <= 1):
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print("Error: --threshold must be between 0 and 1")
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sys.exit(1)
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# Generate output path
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if args.output:
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output_path = Path(args.output)
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# Add .jpg extension if no extension provided
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if not output_path.suffix:
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output_path = output_path.with_suffix('.jpg')
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print(f"No extension specified, using: {output_path}")
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else:
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# Auto-generate output path in results folder with UUID
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results_dir = Path("results")
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results_dir.mkdir(exist_ok=True)
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# Generate 4-character UUID prefix
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uuid_prefix = uuid.uuid4().hex[:4]
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# Include threshold in filename
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threshold_str = f"t{args.threshold}".replace(".", "_")
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output_filename = f"{video_path.stem}_{uuid_prefix}_{threshold_str}.jpg"
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output_path = results_dir / output_filename
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print(f"No output specified, using: {output_path}")
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try:
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if args.debug:
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# Debug mode: analyze changes only
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print("Debug mode: Analyzing changes and generating threshold graph")
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if args.xcolumn is not None:
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print(f"Column mode: Analyzing vertical line at x={args.xcolumn}")
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analyze_changes_only(video_path, x_column=args.xcolumn, debug_output=output_path)
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else:
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print(f"Row mode: Analyzing horizontal line at y={args.yrow}")
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analyze_changes_only(video_path, y_row=args.yrow, debug_output=output_path)
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print("Change analysis completed successfully!")
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else:
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# Normal mode: extract strip photography
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if args.xcolumn is not None:
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print(f"Column mode: Extracting vertical line at x={args.xcolumn}")
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extract_column_strip(video_path, args.xcolumn, output_path, args.threshold)
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else:
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print(f"Row mode: Extracting horizontal line at y={args.yrow}")
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extract_row_strip(video_path, args.yrow, output_path, args.threshold)
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print("Strip photography extraction completed successfully!")
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except Exception as e:
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print(f"Error: {e}")
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sys.exit(1)
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if __name__ == "__main__":
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main() |