[libcamera-devel] [RFC PATCH v1 2/3] pipeline: isp: The software ISP class
Siyuan Fan
siyuan.fan at foxmail.com
Wed Aug 4 09:33:46 CEST 2021
From: Fan Siyuan <siyuan.fan at foxmail.com>
Add the software ISP class only CPU-based. So far the basic alogrithm
includes black level correct, bilinear demosaic interpolation, auto
white balance(gray world), tone mapping(auto contrast), gamma correct.
bilateral filter, 10bit to 8bit compression.
Signed-off-by: Fan Siyuan <siyuan.fan at foxmail.com>
---
src/libcamera/pipeline/isp/isp_processing.cpp | 593 ++++++++++++++++++
src/libcamera/pipeline/isp/isp_processing.h | 62 ++
2 files changed, 655 insertions(+)
create mode 100644 src/libcamera/pipeline/isp/isp_processing.cpp
create mode 100644 src/libcamera/pipeline/isp/isp_processing.h
diff --git a/src/libcamera/pipeline/isp/isp_processing.cpp b/src/libcamera/pipeline/isp/isp_processing.cpp
new file mode 100644
index 00000000..94e8081d
--- /dev/null
+++ b/src/libcamera/pipeline/isp/isp_processing.cpp
@@ -0,0 +1,593 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Siyuan Fan <siyuan.fan at foxmail.com>
+ *
+ * isp_processing.cpp - The software ISP class
+ */
+
+#include "isp_processing.h"
+
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <libcamera/request.h>
+
+#include "libcamera/base/log.h"
+
+namespace libcamera{
+
+LOG_DECLARE_CATEGORY(ISP)
+
+void ISP::autoContrast(uint16_t *data, float lowCut, float highCut, int width, int height)
+{
+ int blue, gr, gb, red;
+ int histBlue[1024] = {0}, histGb[1024] = {0}, histGr[1024] = {0}, histRed[1024] = {0};
+
+ int index;
+ for (int i = 0; i < height; i++) {
+ index = i * width;
+ for (int j = 0; j < width; j++) {
+ if (i % 2 == 0 && j % 2 == 0) {
+ blue = data[index];
+ histBlue[blue]++;
+ }
+ else if ((i % 2 == 0 && j % 2 == 1)) {
+ gb = data[index];
+ histGb[gb]++;
+ }
+ else if ((i % 2 == 1 && j % 2 == 0)) {
+ gr = data[index];
+ histGr[gr]++;
+ }
+ else {
+ red = data[index];
+ histRed[red]++;
+ }
+ index++;
+ }
+ }
+
+ int pixelAmount = width * height;
+ int sum = 0;
+ int minBlue;
+ for (int i = 0; i < 1024; i++){
+ sum = sum + histBlue[i];
+ if (sum >= pixelAmount * lowCut * 0.01) {
+ minBlue = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int maxBlue;
+ for (int i = 1023; i >= 0; i--){
+ sum = sum + histBlue[i];
+ if (sum >= pixelAmount * highCut * 0.01) {
+ maxBlue = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int minGb;
+ for (int i = 0; i < 1024; i++){
+ sum = sum + histGb[i];
+ if (sum >= pixelAmount * lowCut * 0.01) {
+ minGb = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int maxGb;
+ for (int i = 1023; i >= 0; i--){
+ sum = sum + histGb[i];
+ if (sum >= pixelAmount * highCut * 0.01) {
+ maxGb = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int minGr;
+ for (int i = 0; i < 1024; i++){
+ sum = sum + histGr[i];
+ if (sum >= pixelAmount * lowCut * 0.01) {
+ minGr = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int maxGr;
+ for (int i = 1023; i >= 0; i--){
+ sum = sum + histGr[i];
+ if (sum >= pixelAmount * highCut * 0.01) {
+ maxGr = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int minRed;
+ for (int i = 0; i < 1024; i++){
+ sum = sum + histRed[i];
+ if (sum >= pixelAmount * lowCut * 0.01) {
+ minRed = i;
+ break;
+ }
+ }
+
+ sum = 0;
+ int maxRed;
+ for (int i = 1023; i >= 0; i--){
+ sum = sum + histRed[i];
+ if (sum >= pixelAmount * highCut * 0.01) {
+ maxRed = i;
+ break;
+ }
+ }
+
+ int blueMap[1024];
+ float norb = 1.0 / (maxBlue - minBlue);
+ for (int i = 0; i < 1024; i++) {
+ if (i < minBlue) {
+ blueMap[i] = 0;
+ }
+ else if (i > maxBlue) {
+ blueMap[i] = 1023;
+ }
+ else {
+ blueMap[i] = (i - minBlue) * norb * 1023;
+ }
+ if (blueMap[i] > 1023) blueMap[i] = 1023;
+ }
+
+ int gbMap[1024];
+ float norgb = 1.0 / (maxGb - minGb);
+ for (int i = 0; i < 1024; i++) {
+ if (i < minGb) {
+ gbMap[i] = 0;
+ }
+ else if (i > maxGb) {
+ gbMap[i] = 1023;
+ }
+ else {
+ gbMap[i] = (i - minGb) * norgb * 1023;
+ }
+ if (gbMap[i] > 1023) gbMap[i] = 1023;
+ }
+
+ int grMap[1024];
+ float norgr = 1.0 / (maxGr - minGr);
+ for (int i = 0; i < 1024; i++) {
+ if (i < minGr) {
+ grMap[i] = 0;
+ }
+ else if (i > maxGr) {
+ grMap[i] = 1023;
+ }
+ else {
+ grMap[i] = (i - minGr) * norgr * 1023;
+ }
+ if (grMap[i] > 1023) grMap[i] = 1023;
+ }
+
+ int redMap[1024];
+ float norr = 1.0 / (maxRed - minRed);
+ for (int i = 0; i < 1024; i++) {
+ if (i < minRed) {
+ redMap[i] = 0;
+ }
+ else if (i > maxRed) {
+ redMap[i] = 1023;
+ }
+ else{
+ redMap[i] = (i - minRed) * norr * 1023;
+ }
+ if (redMap[i] > 1023) redMap[i] = 1023;
+ }
+
+ for (int i = 0;i < height; i++) {
+ for (int j = 0; j < width; j++){
+ index = i * width;
+ if (i % 2 == 0 && j % 2 == 0) {
+ data[index] = blueMap[data[index]];
+ }
+ else if (i % 2 == 0 && j % 2 == 1) {
+ data[index] = gbMap[data[index]];
+ }
+ else if (i % 2 == 1 && j % 2 == 0) {
+ data[index] = grMap[data[index]];
+ }
+ else {
+ data[index] = redMap[data[index]];
+ }
+ index++;
+ }
+ }
+}
+
+void ISP::blackLevelCorrect(uint16_t *data, uint16_t offset, int width, int height)
+{
+ int len = width * height;
+ for(int i = 0; i < len; i++) {
+ if (data[i] < offset){
+ data[i] = 0;
+ }
+ else {
+ data[i] -= offset;
+ }
+ }
+}
+
+void ISP::readChannels(uint16_t *data, uint16_t *R, uint16_t *G, uint16_t *B,
+ int width, int height)
+{
+ int index;
+ for (int i = 0; i < height; i++) {
+ index = i * width;
+ for (int j = 0; j < width; j++) {
+ if (i % 2 == 0 && j % 2 == 0) {
+ B[index] = data[index];
+ }
+ else if ((i % 2 == 0 && j % 2 == 1) || (i % 2 == 1 && j % 2 == 0)){
+ G[index] = data[index];
+ }
+ else {
+ R[index] = data[index];
+ }
+ index++;
+ }
+ }
+}
+
+void ISP::firstPixelInsert(uint16_t *src, uint16_t *dst, int width, int height)
+{
+ int index;
+ for (int i = 0; i < height; i++) {
+ index = i * width;
+ for (int j = 0; j < width; j++){
+ if (i % 2 == 0 && j % 2 == 1) {
+ if (j == (width - 1)) {
+ dst[index] = src[index - 1];
+ }
+ else {
+ dst[index] = (src[index - 1] +
+ src[index + 1]) >> 1;
+ }
+ }
+
+ if (i % 2 == 1 && j % 2 == 0) {
+ if(i == height - 1) {
+ dst[index] = src[index - width];
+ }
+ else {
+ dst[index] = (src[index - width]+
+ src[index + width]) >> 1;
+ }
+ }
+
+ if (i % 2 == 1 && j % 2 == 1) {
+ if (j < width - 1 && i < height - 1) {
+ dst[index] = (src[index - width - 1] +
+ src[index - width + 1] +
+ src[index + width - 1] +
+ src[index + width + 1]) >> 2;
+ }
+ else if (i == height - 1 && j < width - 1) {
+ dst[index] = (src[index - width - 1] +
+ src[index - width + 1]) >> 1;
+ }
+ else if (i < height - 1 && j == width - 1) {
+ dst[index] = (src[index - width - 1] +
+ src[index + width - 1]) >> 1;
+ }
+ else {
+ dst[index] = src[index - width - 1];
+ }
+ }
+ index++;
+ }
+ }
+}
+
+void ISP::twoPixelInsert(uint16_t *src, uint16_t *dst, int width, int height)
+{
+ int index;
+ for (int i = 0; i < height; i++) {
+ index = i * width;
+ for (int j = 0; j < width; j++) {
+ if (i == 0 && j == 0) {
+ dst[index] = (src[index + width] +
+ src[index + 1]) >> 1;
+ }
+ else if (i == 0 && j > 0 && j % 2 == 0) {
+ dst[index] = (src[index - 1] +
+ src[index + width] +
+ src[index + 1]) / 3;
+ }
+ else if (i > 0 && j == 0 && i % 2 == 0) {
+ dst[index] = (src[index - width] +
+ src[index + 1] +
+ src[index + width]) / 3;
+ }
+ else if (i == (height - 1) && j < (width - 1) && j % 2 == 1) {
+ dst[index] = (src[index - 1] +
+ src[index - width] +
+ src[index + 1]) / 3;
+ }
+ else if (i < (height - 1) && j == (width - 1) && i % 2 == 1) {
+ dst[index] = (src[index - width] +
+ src[index - 1] +
+ src[index + width]) / 3;
+ }
+ else if (i == (height - 1) && j == (width - 1)) {
+ dst[index] = (src[index - width] +
+ src[index - 1]) >> 1;
+ }
+ else if ((i % 2 == 0 && j % 2 == 0) || (i % 2 == 1 && j % 2 == 1)) {
+ dst[index] = (src[index - 1] +
+ src[index + 1] +
+ src[index - width] +
+ src[index + width]) / 4;
+ }
+ index++;
+ }
+ }
+}
+
+void ISP::lastPixelInsert(uint16_t *src, uint16_t *dst, int width, int height)
+{
+ int index;
+ for (int i = 0; i < height; i++) {
+ index = i * width;
+ for (int j = 0; j < width; j++){
+ if (i % 2 == 1 && j % 2 == 0) {
+ if (j == 0) {
+ dst[index] = src[index + 1];
+ }
+ else {
+ dst[index] = (src[index - 1] +
+ src[index + 1]) >> 1;
+ }
+ }
+
+ if (i % 2 == 0 && j % 2 == 1) {
+ if(i == 0) {
+ dst[index] = src[index + width];
+ }
+ else {
+ dst[index] = (src[index - width]+
+ src[index + width]) >> 1;
+ }
+ }
+
+ if (i % 2 == 0 && j % 2 == 0) {
+ if (i > 0 && j > 0) {
+ dst[index] = (src[index - width - 1] +
+ src[index - width + 1] +
+ src[index + width - 1] +
+ src[index + width + 1]) >> 2;
+ }
+ else if (i == 0 && j > 0) {
+ dst[index] = (src[index + width - 1] +
+ src[index + width + 1]) >> 1;
+ }
+ else if (i > 0 && j == 0) {
+ dst[index] = (src[index - width + 1] +
+ src[index + width + 1]) >> 1;
+ }
+ else {
+ dst[index] = src[index + width + 1];
+ }
+ }
+ index++;
+ }
+ }
+}
+
+void ISP::demosaic(uint16_t *data, uint16_t *R, uint16_t *G, uint16_t *B,
+ int width, int height)
+{
+ firstPixelInsert(data, B, width, height);
+ twoPixelInsert(data, G, width, height);
+ lastPixelInsert(data, R, width, height);
+}
+
+void ISP::autoWhiteBalance(uint16_t *R, uint16_t *G, uint16_t *B, int width, int height)
+{
+ float aveB = 0, aveG = 0, aveR = 0;
+ float Kb, Kg, Kr;
+
+ for (int i = 0; i < width * height; i++) {
+ aveB += 1.0 * B[i];
+ aveG += 1.0 * G[i];
+ aveR += 1.0 * R[i];
+ }
+
+ aveB *= (1.0 / (width * height));
+ aveG *= (1.0 / (width * height));
+ aveR *= (1.0 / (width * height));
+
+ Kr = (aveB + aveG + aveR) / aveR * (1.0 / 3.0);
+ Kg = (aveB + aveG + aveR) / aveG * (1.0 / 3.0);
+ Kb = (aveB + aveG + aveR) / aveB * (1.0 / 3.0);
+
+ for (int i = 0; i < width * height; i++) {
+ B[i] = B[i] * Kb;
+ G[i] = G[i] * Kg;
+ R[i] = R[i] * Kr;
+
+ if (R[i] > 1023) R[i] = 1023;
+ if (G[i] > 1023) G[i] = 1023;
+ if (R[i] > 1023) B[i] = 1023;
+ }
+}
+
+void ISP::gammaCorrect(uint16_t *R, uint16_t *G, uint16_t *B, float val,
+ int width, int height)
+{
+ float nor = 1.0 / 1023.0;
+ float gamma = 1.0 / val;
+ for (int i = 0; i < width * height; i++) {
+ R[i] = pow(R[i] * nor, gamma) * 1023;
+ G[i] = pow(G[i] * nor, gamma) * 1023;
+ B[i] = pow(B[i] * nor, gamma) * 1023;
+
+ if (R[i] > 1023) R[i] = 1023;
+ if (G[i] > 1023) G[i] = 1023;
+ if (B[i] > 1023) B[i] = 1023;
+ }
+}
+
+void ISP::compress_10bit_to_8bit (uint16_t *src, uint8_t *dst, int width, int height)
+{
+ for (int i = 0; i < width * height; i++) {
+ dst[i] = src[i] >> 2 & 0xff;
+ }
+}
+
+float ISP::distance(int x, int y, int i, int j)
+{
+ return float(sqrt(pow(x - i, 2) + pow(y - j, 2)));
+}
+
+double ISP::gaussian(float x, double sigma)
+{
+ return exp(-(pow(x, 2)) / (2 * pow(sigma, 2))) / (2 * 3.1415926 * pow(sigma, 2));
+}
+
+void ISP::bilateralFilter(uint16_t *R, uint16_t *G, uint16_t *B,
+ int diameter, double sigmaI,
+ double sigmaS, int width, int height)
+{
+ for (int i = 2; i < height - 2; i++) {
+ for (int j = 2; j < width - 2; j++) {
+ double iFiltered = 0;
+ double wp = 0;
+ int neighbor_x = 0;
+ int neighbor_y = 0;
+ int half = diameter / 2;
+
+ for (int k = 0; k < diameter; k++) {
+ for (int l = 0; l < diameter; l++) {
+ neighbor_x = i - (half - k);
+ neighbor_y = j - (half - l);
+ double gi = gaussian(R[neighbor_x * width + neighbor_y] - R[i * width +j], sigmaI);
+ double gs = gaussian(distance(i, j, neighbor_x, neighbor_y), sigmaS);
+ double w = gi * gs;
+ iFiltered = iFiltered + R[neighbor_x * width + neighbor_y] * w;
+ wp = wp + w;
+ }
+ }
+
+ iFiltered = iFiltered / wp;
+ R[i * width + j] = iFiltered;
+ }
+ }
+
+ for (int i = 2; i < height - 2; i++) {
+ for (int j = 2; j < width - 2; j++) {
+ double iFiltered = 0;
+ double wp = 0;
+ int neighbor_x = 0;
+ int neighbor_y = 0;
+ int half = diameter / 2;
+
+ for (int k = 0; k < diameter; k++) {
+ for (int l = 0; l < diameter; l++) {
+ neighbor_x = i - (half - k);
+ neighbor_y = j - (half - l);
+ double gi = gaussian(G[neighbor_x * width + neighbor_y] - G[i * width +j], sigmaI);
+ double gs = gaussian(distance(i, j, neighbor_x, neighbor_y), sigmaS);
+ double w = gi * gs;
+ iFiltered = iFiltered + G[neighbor_x * width + neighbor_y] * w;
+ wp = wp + w;
+ }
+ }
+
+ iFiltered = iFiltered / wp;
+ G[i * width + j] = iFiltered;
+ }
+ }
+
+ for (int i = 2; i < height - 2; i++) {
+ for (int j = 2; j < width - 2; j++) {
+ double iFiltered = 0;
+ double wp = 0;
+ int neighbor_x = 0;
+ int neighbor_y = 0;
+ int half = diameter / 2;
+
+ for (int k = 0; k < diameter; k++) {
+ for (int l = 0; l < diameter; l++) {
+ neighbor_x = i - (half - k);
+ neighbor_y = j - (half - l);
+ double gi = gaussian(B[neighbor_x * width + neighbor_y] - B[i * width +j], sigmaI);
+ double gs = gaussian(distance(i, j, neighbor_x, neighbor_y), sigmaS);
+ double w = gi * gs;
+ iFiltered = iFiltered + B[neighbor_x * width + neighbor_y] * w;
+ wp = wp + w;
+ }
+ }
+
+ iFiltered = iFiltered / wp;
+ B[i * width + j] = iFiltered;
+ }
+ }
+}
+
+void ISP::processing(FrameBuffer *srcBuffer, FrameBuffer *dstBuffer, int width, int height)
+{
+ uint8_t *rgb_buf;
+ uint16_t *rawData;
+ uint16_t *rgbData = new std::uint16_t[width * height * 3];
+
+ uint16_t *rData = rgbData;
+ uint16_t *gData = rData + width * height;
+ uint16_t *bData = gData + width * height;
+ memset(rgbData, 0x0, width * height * 3);
+
+ const FrameBuffer::Plane &plane = srcBuffer->planes()[0];
+ rawData = (uint16_t *)mmap(NULL, plane.length, PROT_READ|PROT_WRITE, MAP_SHARED, plane.fd.fd(), 0);
+ if (rawData == MAP_FAILED) {
+ LOG(ISP, Error) << "Read raw data failed";
+ ispCompleted.emit(dstBuffer);
+ }
+
+ blackLevelCorrect(rawData, 16, width, height);
+ readChannels(rawData, rData, gData, bData, width, height);
+ demosaic(rawData, rData, gData, bData, width, height);
+ autoWhiteBalance(rData, gData, bData, width, height);
+ autoContrast(rData, 0.01, 0.01, width, height);
+ autoContrast(gData, 0.01, 0.01, width, height);
+ autoContrast(bData, 0.01, 0.01, width, height);
+ gammaCorrect(rData, gData, bData, 2.2, width, height);
+ //bilateralFilter(rData, gData, bData, 5, 24.0, 32.0);
+
+ const FrameBuffer::Plane &rgbPlane = dstBuffer->planes()[0];
+ rgb_buf = (uint8_t *)mmap(NULL, rgbPlane.length, PROT_READ|PROT_WRITE, MAP_SHARED, rgbPlane.fd.fd(), 0);
+ if (rgb_buf == MAP_FAILED) {
+ LOG(ISP, Error) << "Read rgb data failed";
+ ispCompleted.emit(dstBuffer);
+ }
+
+ uint8_t *rData_8 = rgb_buf;
+ uint8_t *gData_8 = rData_8 + width * height;
+ uint8_t *bData_8 = gData_8 + width * height;
+
+ compress_10bit_to_8bit(rData, rData_8, width, height);
+ compress_10bit_to_8bit(gData, gData_8, width, height);
+ compress_10bit_to_8bit(bData, bData_8, width, height);
+
+ delete[] rgbData;
+
+ ispCompleted.emit(dstBuffer);
+}
+
+} /* namespace libcamera */
+
diff --git a/src/libcamera/pipeline/isp/isp_processing.h b/src/libcamera/pipeline/isp/isp_processing.h
new file mode 100644
index 00000000..b80b4218
--- /dev/null
+++ b/src/libcamera/pipeline/isp/isp_processing.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Siyuan Fan <siyuan.fan at foxmail.com>
+ *
+ * isp_processing.h - The software ISP class
+ */
+#ifndef __LIBCAMERA_PIPELINE_ISP_PROCESSING_H__
+#define __LIBCAMERA_PIPELINE_ISP_PROCESSING_H__
+
+#include <libcamera/framebuffer.h>
+
+#include "libcamera/base/signal.h"
+#include "libcamera/base/object.h"
+
+namespace libcamera{
+
+using std::uint16_t;
+using std::uint8_t;
+
+class ISP : public Object
+{
+public:
+ void autoContrast(uint16_t *data, float lowCut, float highCut, int width, int height);
+
+ void blackLevelCorrect(uint16_t *data, uint16_t offset, int width, int height);
+
+ void readChannels(uint16_t *data, uint16_t *R, uint16_t *G, uint16_t *B,
+ int width, int height);
+
+ void firstPixelInsert(uint16_t *src, uint16_t *dst, int width, int height);
+
+ void twoPixelInsert(uint16_t *src, uint16_t *dst, int width, int height);
+
+ void lastPixelInsert(uint16_t *src, uint16_t *dst, int width, int height);
+
+ void demosaic(uint16_t *data, uint16_t *R, uint16_t *G, uint16_t *B,
+ int width, int height);
+
+ void autoWhiteBalance(uint16_t *R, uint16_t *G, uint16_t *B, int width, int height);
+
+ void gammaCorrect(uint16_t *R, uint16_t *G, uint16_t *B, float val,
+ int width, int height);
+
+ float distance(int x, int y, int i, int j);
+
+ double gaussian(float x, double sigma);
+
+ void bilateralFilter(uint16_t *R, uint16_t *G, uint16_t *B,
+ int diameter, double sigmaI, double sigmaS,
+ int width, int height);
+
+ void compress_10bit_to_8bit(uint16_t *src, uint8_t *dst, int width, int height);
+
+ void processing(FrameBuffer *srcBuffer, FrameBuffer *dstBuffer, int width, int height);
+
+ Signal<FrameBuffer *> ispCompleted;
+
+};
+
+}
+
+#endif /* __LIBCAMERA_PIPELINE_ISP_PROCESSING_H__ */
--
2.20.1
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